Still, Iran’s move raises the pressure on the West for some reciprocal gestures to keep dialogue on track and further highlights Tehran’s apparent aims of opening a long give-and-take process over its nuclear ambitions.

A major breakthrough in the yearslong impasse was not expected in Baghdad, with officials and experts saying both sides will seek to demonstrate enough progress to keep the process moving forward.

That could cool down worries in international markets over possible military action, but reinforce the suspicions of Israeli leaders who claim Iran seeks only to buy time to keep up its production of nuclear fuel.

Iran’s envoys, meanwhile, promoted the Baghdad round as an opportunity to set aside past obstacles.

“That is the basis for the beginning of a new cooperation,” said Saeed Jalili, the top Iranian nuclear negotiator, who arrived in Baghdad late Monday. “We hope that the talks in Baghdad will be a kind of dialogue that will give shape to such cooperation.”

Iran’s ambassador to Iraq, Hasan Danaeifar, said the Baghdad talks could be historic.

“Should the talks set a start for a serious, constructive settlement of the issues, it could be a historic meeting for all sides,” the official IRNA news agency quoted him as saying.

A senior Western diplomat in Baghdad said sanctions on Iran’s oil exports, set to take effect July 1, likely pushed Tehran to the bargaining table.

“I don’t think the Iranians are coming to these talks because they suddenly changed their minds about anything. They are coming to these talks because sanctions are beginning to bite,” the diplomat said in an interview this week with The Associated Press. He spoke on condition of anonymity to discuss the negotiations candidly.

In Iranian terms, that means offering some possible accommodations — such as opening to greater U.N. inspections — but sticking to its right to enrich uranium as a signatory of U.N. nuclear treaties. The Baghdad talks, involving the five permanent U.N. Security Council members plus Germany, could offer a test of how much the U.S. and allies are willing to bend from demands for Iran to halt to all enrichment and instead concentrate on just stopping the highest-grade production.

The West and others fear the 20 percent-level enrichment can be turned quickly into weapons-grade of over 90 percent.

Iran has repeatedly denied it seeks nuclear arms and says its reactors are only for power and medical research.

On Tuesday, the official Islamic Republic News Agency reported that Iranian scientists had inserted a domestically made fuel rod, which contains pellets of 20 percent enriched uranium, into the core of a research nuclear reactor in Tehran.

The advance would be another step in achieving proficiency in the entire nuclear fuel cycle. Iran said in January that it had produced the first nuclear fuel rod, and that it had to find a way to make them because Western sanctions prohibit their purchase from foreign markets.

Western claims about a clandestine atomic weapons program have often cited Iran’s Parchin military facility, where the U.N.’s International Atomic Energy Agency believes Iran in 2003 ran explosive tests needed to set off a nuclear charge. Iran describes Parchin as a conventional military site.

The agency’s chief, Yukiya Amano, returned to Vienna on Tuesday from a one-day trip to Tehran and said an agreement is within reach to give inspectors “access to sites, scientists and documents it seeks to restart its probe.”

He noted that some differences still exist but claimed they “will not be an obstacle to reach agreement.” He gave no details on the unsettled points or when the pact could be signed.

Amano’s remarks brought a measured response from Washington and allies.

Robert A. Wood, the chief U.S. delegate to the nuclear agency, said Amano’s efforts were appreciated but Washington remains “concerned by the urgent obligation for Iran to take concrete steps to cooperate fully with the verification efforts of the IAEA, based on IAEA verification practices.”

“We urge Iran to take this opportunity to resolve all outstanding concerns about the nature of its nuclear program,” Wood said in a statement. “Full and transparent cooperation with the IAEA is the first logical step.”

In Germany, Foreign Minister Guido Westerwelle said the apparent inspection pact was an “overdue step in the right direction.”

But he added: “The aim is to make progress not just atmospherically but also on substance.”

Israel’s defense minister, Ehud Barak, dismissed it as a “deception of progress” to save off international pressure.

“It looks like the Iranians are trying to reach a technical agreement that will create a deception of progress in talks in order to reduce the pressure ahead of talks tomorrow in Baghdad and postpone harshening of sanctions,” Barak said, according to a statement from his office.

On Monday, the U.S. Senate backed proposals for further sanctions on Iran, including requiring companies listed on U.S. stock exchanges to disclose any Iran-related business. U.S. and European measures already have targeted Iran’s oil exports — its chief revenue source — and effectively blocked the country from international banking networks.

Even before the meetings begin in Baghdad, expectations were kept in check.

Iraqi Foreign Minister Hoshyar Zebari said they will “not produce a miracle.”

“But everybody is looking for some tangible steps on the basis of reciprocity,” Zebari told AP in an interview.

Zebari said there is consensus in Iran for the first time to reach a diplomatic deal.

Mahdi Mohtashami, an analyst and former Iranian foreign ministry official, said “the two sides should begin with small steps, not big demands, if they are to make any progress.”

The U.S. has been vague about its immediate goals, with officials saying the talks will gauge Iran’s seriousness and explore elements of a possible agreement.

President Barack Obama opposes a near-term military strike on Iran’s nuclear facilities. He has pressed Israel to give diplomacy and sanctions time to work while insisting that military options are available should talks fail. Republicans have criticized Obama for holding talks with Iran at all.

The West has made clear that Iran must show evidence that its nuclear program is peaceful before it will even consider lifting sanctions.

“What we need to begin to get things started is something concrete, real and detailed from the Iranians,” said the senior Western diplomat in Baghdad. Chances for a final resolution in Baghdad are “very slim,” he said. “There is no question of sanctions being lifted in exchange for promises, or in exchange for words on a piece of paper.”

Fierce sandstorms since Monday have closed Baghdad’s airport and could disrupt travel plans for some participants in the talks.

Having Baghdad as the venue is a symbolic victory for Iran and a showcase of its deep influence in the country more than nine years after U.S.-led forces toppled Tehran’s archenemy, Saddam Hussein.

Iran pushed for Baghdad as a way to boost the international prestige of the Iraqi government, which has close ties to Tehran. The talks also will take place inside the Green Zone, which was once the hub of U.S. political and military operations after the 2003 invasion.

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Associated Press writers George Jahn in Vienna, Brian Murphy in Dubai and Josef Federman in Jerusalem contributed to this report.

Any concessions — either too great or too fast — could risk internal rifts within Iran’s power structure. And that could draw powerful forces into the mix, including the Revolutionary Guard that acts as defender of the theocracy and overseer of the nuclear program. As talks deepen, so do the political considerations for an Islamic establishment that cannot afford to appear to come away empty handed.

“Insisting on a halt to enrichment is a deal breaker,” said Tehran-based political analyst Behrooz Shojaei. “It is Iran’s red line.”

This means smaller targets are likely necessary to keep dialogue alive after the Baghdad session next Wednesday between Iran and the six-nation group comprising the permanent U.N. Security Council members plus Germany.

A possible steppingstone goal for the U.S. and allies is to seek to halt Iran’s production of uranium enriched to 20 percent levels, the highest-grade material acknowledged by Tehran. The enrichment level is far above what’s needed for Iran’s lone energy-producing reactor, but it is appropriate for use in medical research. It also could be boosted to weapons-grade strength in a matter of months.

Iran insists it has no interest in developing atomic weapons, but it sees its uranium labs as a mainstay of its technological advances that include long-range missiles and an aerospace program that has promised another satellite launch this month. There still could be some room, however, for bargaining.

Iran has signaled it could consider ending the 20 percent enrichment. In return, though, it wants Washington and Europe to ease some of the most painful new sanctions, including those hitting Iran’s oil exports and its access to international banking networks.

Such demands would directly test the West’s flexibility.

Previously, Washington and European allies have insisted that Iran must take the first step and suspend all uranium enrichment as required by several U.N. Security Council resolutions. They also are under pressure from Israel to avoid protracted give-and-take negotiations.

Last week, the European Union’s foreign policy chief Catherine Ashton met with Israeli officials, including Prime Minister Benjamin Netanyahu, to discuss the upcoming talks. Later, Ashton said she hoped for “concrete” results in Baghdad.

But the semiofficial Fars news agency quoted Gen. Yadollah Javani, a Revolutionary Guard adviser, as saying it’s too early to be optimistic.

“Iran does not trust the West,” he said. “The West should build the trust in the long run.”

Netanyahu derided the opening round of talks last month in Istanbul, mocking them as a “freebie” that gave Iran international cover to continue enriching uranium. Iran, in turn, has accused Israel of trying to destroy the negotiations as pretext to a possible military strike.

“All the sides are moving with extreme caution,” said Mustafa Alani, a regional affairs analyst at the Gulf Research Center based in Geneva. “It seems no one wants to give too much or say too much at this stage. But also no one wants to be portrayed as the side that killed the talks.”

This is the tricky ground being navigated by Iran.

Its leaders are desperate to avoid any impression of caving under the Western economic squeeze. Any serious rollbacks — without Western concessions in return — could open room for hard-liners to take pot shots at the ruling clerics. It also could put the Revolutionary Guard in the awkward position of defending the Islamic system against ultra-nationalists who normally side with the Guard.

The timing, too, brings added concerns for Iran.

Ahmadinejad is moving into his last year in office and the ruling theocracy is closely watching for any signs of an opposition resurgence before next year’s elections. It took months for the Revolutionary Guard to snuff out unprecedented street protests after Ahmadinejad’s disputed re-election in June 2009. Then the ruling system turned against Ahmadinejad last year after he tried to challenge the authority of Supreme Leader Ayatollah Ali Khamenei.

“Too much political capital has been invested in the nuclear program for … Khamenei to simply slink away and retreat,” wrote Iranian affairs analyst Afshin Molavi in Tuesday’s edition of The National newspaper in Abu Dhabi.

Even after the feuds with Khamenei, Ahmadinejad has been a loyal advocate to Iran’s negotiating positions at the talks.

“If the Westerners change their attitudes and pay respect to the Iranian nation, they will be treated respectfully by Iranians, in return,” Ahmadinejad said Monday during a tour of eastern Iran.

He added: “They should know that Iranian nation will not take a single step back from their basic rights” — a clear reference to uranium enrichment.

In Vienna, envoys from Iran and the U.N. nuclear agency held a second day of talks over suspicions that Tehran might have tested atomic arms technology at a military site. Iran denies the claims.

The International Atomic Energy Agency has sought access to the Parchin base for more than four years. It also wants to interview scientists and review documents.

The IAEA believes Iran in 2003 ran explosive tests needed to set off a nuclear charge. The suspected blasts took place inside a pressure chamber, the agency said.

A senior diplomat familiar with the IAEA probe says Iran has never said whether the chamber existed. A computer-generated drawing provided to The Associated Press by a nation critical of Iran’s nuclear program shows such a structure. The official who shared it said the drawing was based on information from someone who saw the chamber.

Iranian envoy Ali Asghar Soltanieh told reporters in Vienna “everything is on the right track.” He described the atmosphere as “very constructive.”

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Murphy reported from Dubai, United Arab Emirates. Associated Press writer George Jahn in Vienna contributed to this report.

Iran claims that Israel and the U.S. are trying to disrupt its nuclear program through covert operations. Israel, which is widely believed to have nuclear weapons but has neither confirmed nor denied it, accuses Iran of seeking to develop an atomic bomb.

Iran has denied it seeks nuclear weapons and insists its uranium enrichment program is for peaceful purposes only, such as generating electricity and nuclear isotopes to treat cancer patients.

At least five Iranian nuclear scientists, including a manager at the Natanz enrichment facility, have been killed in recent years. Tehran has accused Israel’s Mossad, the CIA and Britain’s MI-6 of being behind the assassinations. The U.S. and Britain have denied the allegations but Israel has remained silent on the issue.

Jamali Fashi, 24, was tried and convicted last August, and subsequently sentenced to death in Mohammadi’s killing. His lawyer appealed the verdict but Iran’s Supreme Court upheld the execution order issued by a lower court, paving the way for the hanging.

During the trial, he was accused of cooperating with Mossad, traveling to Israel to attend a Mossad training course and receiving money from the Israeli intelligence service.

Last year, Iran’s state TV broadcast what it said were confessions by Jamali Fashi in which he admitted that he was recruited by Mossad.

The president rebuffed Republican critics, who say his reluctance to attack Iran is a sign of weakness, holding up the specter of more dead Americans in another Mideast war.

“When I see the casualness with which some of these folks talk about war, I’m reminded of the costs involved in war,” Obama said. “This is not a game. And there’s nothing casual about it.”

Although Obama’s remarks were suffused with American election-year politics — they came the same day as the biggest batch of Republican primaries to choose his opponent in November — he spoke for capitals around the world in warning that “bluster” and posturing to appear tough on Iran could edge the world closer to an avoidable war.

European Union foreign policy chief Catherine Ashton said the five permanent members of the U.N. Security Council and Germany had agreed to a new round of nuclear talks with Iran more than a year after suspending them in frustration.

Previous talks have not resolved international suspicions that Iran is engaging in a nuclear energy program as cover for an eventual plan to build a bomb. On a practical level, the negotiating group also has failed to strike a deal for Iran to stop enriching uranium that might one day be turned into bomb fuel.

The rush to diplomacy was partly an answer to increasingly hawkish rhetoric from Israel, which is publicly considering a military strike on Iranian nuclear facilities this spring. Obama and Western allies say such a strike would be risky and premature, and that there is still time to persuade Iran that it is better off without nuclear weapons.

Iran insists that its program is only for energy production and other peaceful purposes.

In sitting down with Iran, Ashton said negotiators want “constructive dialogue” that will deliver real progress in resolving the international community’s long-standing concerns on its nuclear program.”

The time and venue of the new talks have not been set.

Iran has a history of agreeing to talks or other concessions when it feels under threat, and Western leaders have grown skeptical that Iran will bargain in good faith..

Following gatherings in five-star European hotels, Iran often publicly rejects pressure but privately agrees to small compromises. Diplomats return home to consult their presidents and prime ministers, and Iran, the theory goes, presses on with its nuclear development work.

However, initially mild economic sanctions on Iran have grown stronger and more difficult for the government to circumvent. The oil-rich country is still able to sell its oil, mostly in Asia, but labors under severe banking restrictions that will get far tougher this summer. Europe also imposed an unprecedented oil embargo on Iran, to take effect in July.

Obama and others said diplomacy and such sanctions should be given more time

Iran appeared to partially answer concerns Tuesday from the U.N.’s International Atomic Energy Agency that it has something to hide, by announcing long-sought access to its Parchin military complex southeast of Tehran. The IAEA has singled out the complex, which Iran had long refused to open for inspection.

Terms appeared limited and unclear in Iran’s announcement.

In Washington, speaking at his first news conference this year, Obama said he saw a “window of opportunity” to use diplomacy instead of military force to resolve the dispute. He declared anew that his policy on Iran is not one of containment but of stopping Tehran from acquiring a nuclear weapon.

Britain’s foreign secretary, William Hague, said the onus would “be on Iran to convince the international community that its nuclear program is exclusively peaceful.”

German Foreign Minister Guido Westerwelle called for a diplomatic solution. “A nuclear-armed Iran must be prevented,” he said

Obama publicly rejected the assertion, heard most loudly from Republicans and Israelis, that the window for diplomacy was closing.

“It is deeply in everybody’s interests — the United States, Israel and the world’s — to see if this can be resolved in a peaceful fashion,” Obama said. “This notion that somehow we have a choice to make in the next week or two weeks or month or two months is not borne out by the facts.”

A day earlier, Netanyahu said Israel could not afford to wait much longer. Following a lengthy meeting with Obama at the White House, he accused Iran of a shell game that allows it to get ever closer to a bomb.

A leading Democratic senator emerged from discussions with Netanyahu on Tuesday saying he was convinced that an Israeli strike was likely. Asked whether he had made such a decision, Netanyahu would say only that he had decided not to talk about it.

“I think it’s likely because Iran is not responding to the international call for it to abide by the U.N. resolutions,” said Senate Armed Services Committee Chairman Carl Levin, D-Mich. “Iran is violating six different U.N. resolutions. I think that being the case, they continue to do it, don’t open up their uranium facilities to inspection and don’t stop the enrichment of uranium, then I would say an attack on them by Israel is very likely.”

The impact of the Iran debate on domestic American politics was underscored as Mitt Romney, Rick Santorum and Newt Gingrich took time while competing for votes in the high-stakes Super Tuesday primaries to join the speakers’ lineup at the same pro-Israel gathering that was part of the reason for Netanyahu’s trip to Washington.

Santorum appeared in person and immediately criticized Tuesday’s offer by the United States, European countries, Russia and China to resume talks with Iran. He termed it “another appeasement, another delay, another opportunity for them to go forward while we talk.”

Romney, in a video appearance, assailed the administration’s approach on Iran, saying, “Hope is not a foreign policy.”

Israel’s national security adviser, Yaakov Amidror, said that his nation had achieved its objective of putting Iran at the top of the agenda in Washington and beyond while spelling out to the U.S. that Israel will decide how best to defend itself.

“I leave with the sense that we as Israelis have to sit down among ourselves and digest what the Americans told us,” Amidor said.

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Ali Akbar Dareini reported from Tehran. Associated Press writers George Jahn in Vienna and Donna Cassata and Amy Teibel in Washington contributed to this report.

He said he is focused on “crippling sanctions” already imposed on Iran and on international pressure to keep Tehran from developing a nuclear weapon. Iranians need to show they are serious about resolving the crisis, he said, adding that his policy is not one of containment but of stopping Iran from acquiring a nuclear weapon.

The U.S. and its allies say Iran is on a path that could lead to the production of a nuclear weapon. Iran denies that, insisting its program is for energy production and other peaceful purposes.

Speaking in Brussels, EU foreign policy chief Catherine Ashton said the five permanent members of the U.N. Security Council and Germany had agreed to a new round of nuclear talks with Iran. Previous talks have not achieved what the powers want — an end to uranium enrichment on Iranian soil. The last round ended in failure in January 2011.

Ashton said the EU hopes Iran “will now enter into a sustained process of constructive dialogue which will deliver real progress in resolving the international community’s long-standing concerns on its nuclear program.”

The time and venue of the new talks have not yet been set.

Britain’s foreign secretary, William Hague, said the onus would “be on Iran to convince the international community that its nuclear program is exclusively peaceful.”

German Foreign Minister Guido Westerwelle called for a diplomatic solution. “A nuclear-armed Iran must be prevented,” he said.

This week Obama warned the U.S. would use military action to protect its interests if necessary, while appealing for time for sanctions against Iran to show their affects. In his public statements during a visit to Washington, Israeli Prime Minister Benjamin Netanyahu thanked Obama for his support but did little to counter concerns that Israel might go ahead on its own with an attack on Iran. Israel considers Iran an existential threat because of its nuclear program and its references to destruction of the Jewish state.

On Tuesday, Obama implied that Israeli pressure for urgent action was not supported by the facts, saying that a decision was not necessary within the next weeks or months.

The U.N.’s International Atomic Energy Agency last year published a report that included what it said was evidence of Iranian activity that could be linked to weapons development. The head of the IAEA, Yukiya Amano, said Monday that his organization has “serious concerns” that Iran may be hiding secret atomic weapons work, singling out the Parchin military complex southeast of Tehran.

On Tuesday, Iran appeared to respond partially to those concerns, granting long-sought permission to IAEA inspectors to visit the Parchin compound. Iran describes the site as a military base, not a nuclear facility.

The semi-official ISNA news agency stated a key condition: such a visit would require an agreement between the two sides on guidelines.

“Given that Parchin is a military site, access to this facility is a time-consuming process, and it can’t be visited repeatedly,” ISNA quoted the Iranian statement as saying. It added that following repeated IAEA demands, “permission will be granted for access once more.”

Inspecting Parchin was a key request by senior IAEA teams that visited Tehran in January and February. Iran rebuffed those demands at the time, as well as attempts by the nuclear agency’s team to question Iranian officials and secure other information linked to the allegations of secret weapons work.

The Parchin complex has been often mentioned in the West as a suspected base for secret nuclear experiments — a claim Iran consistently denies. IAEA inspectors visited the site in 2005, but only one of four areas on the grounds, reporting no unusual activities.

Last year, the IAEA’s report said there were indications Tehran has conducted high-explosives testing to set off a nuclear charge at Parchin. Iran denied the atomic activity and insisted that any decision to open the site rests with the armed forces.

“We have our credible information that indicates that Iran engaged in activities relevant to the development of nuclear explosive devices,” Amano said told reporters Monday outside a 35-nation IAEA board meeting in Vienna, describing his sources as “old information and new information.”

Tehran has dismissed the charge, saying it was based on “fabricated documents” provided by a “few arrogant countries,” a phrase Iranian authorities often use to refer to the U.S. and its allies.

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Associated Press writers George Jahn in Vienna, Ben Feller in Washington, David Rising in Berlin and Raf Casert in Brussels contributed to this report.