The observers, members of an eight-member advance team that has been on the ground a week, were seen on amateur video Saturday walking through rubble-strewn deserted streets lined by gutted apartment buildings. Activists reported only sporadic gunfire, but no shelling, and said troops had pulled armored vehicles off the streets. Two observers stayed behind in Homs to keep monitoring the city, after the rest of the team left Saturday evening.

The mission approved Saturday, initially for 90 days, is meant to shore up a cease-fire that officially took effect 10 days ago, but has failed to halt violence. U.N. chief Ban Ki-moon has accused Assad of violating the truce, and said Saturday that “the gross violations of the fundamental rights of the Syrian people must stop at once.” Rebel fighters have also kept up attacks.

It’s the first time the Security Council authorized unarmed U.N. military observers to go into a conflict area. Saturday’s resolution gave Ban the final say on when to deploy them, based on his assessment of the situation.

A previous observer team, dispatched by the Arab League at the start of the year, withdrew after a month, unable to halt the fighting.

Western diplomats put the onus on Syria to make the mission work. The U.S. ambassador, Susan Rice, warned that the U.S. would pursue sanctions if Assad doesn’t comply. Britain’s envoy,Mark Lyall Grant, said that “the mission will fail in its task if the regime continues to violate its commitments and obstructs the work of the mission.”

The truce and the observer mission are part of special envoy Kofi Annan’s plan for ending 13 months of violence and launching talks between Assad and those trying to oust him. Syria’s opposition and its Western supporters suspect Assad is largely paying lip service to the cease-fire since full compliance could quickly sweep him from power.

So far, the regime has ignored such provisions and instead continued attacking opposition strongholds, though on a smaller scale than before the truce deadline.

Syria’s U.N. ambassador, Bashar Ja’afari, told the Security Council that Syria informed Annan on Saturday that it has withdrawn troops and heavy weapons from urban centers, but he did not make clear when it occurred. Opposition activists said that in some areas, such as Homs, armored vehicles were moved off the streets Saturday, but remained near populated areas.

Rice, in the toughest speech on Syria yet, warned that if Assad doesn’t make good on all commitments or obstructs the monitors’ work, the United States would pursue other “measures,” which in diplomatic language usually means sanctions.

“Let there be no doubt. We, our allies and others in this body are planning and preparing for those actions that will be required of all of us if the Assad regime persists in the slaughter of the Syrian people,” she said, adding the U.S. will not wait 90 days to take these measures if Syria keeps flouting its obligations.

Despite the violations, the international community sees Annan’s plan as the only way forward.

Russia and China have shielded their ally Syria against Security Council condemnation, Western powers oppose military intervention and Gulf country have failed to keep promises of funding rebels.

On Saturday, five observers toured rebel-held areas in Homs, a center of the uprising that has been battered by tank and mortar shells for weeks. Previously, the Syrian regime, citing security issues, had turned down a request by the observers to visit the city.

“We did not hear any shelling today,” said a Homs activist, who only identified himself as Abul-Joud, for fear of repercussions.

At one point, gunfire went off in the distance while the observers were in the Bayada neighborhood, accompanied by residents. The group ran into a house to take cover, according to Abul-Joud, who said he was walking with the observers. He said it did not appear the shots were aimed in the direction of the monitors.

In the Jouret el-Shayah neighborhood of Homs, observers were quickly thronged by residents who chanted, “The people want military intervention,” according to video broadcast on the Al-Jazeera satellite TV station.

The observers walked silently through the streets in amateur video from the same neighborhood, posted online Saturday. A man in military uniform, apparently a rebel, pointed to the destruction, telling the team that “it’s all destroyed buildings.” Dozens of residents chanted, “The people want to execute the president,” and “Freedom forever, against your will, Assad.”

A spokesman for the observers, Neeraj Singh, said two observers stayed on after Saturday’s tour “and have now been deployed in Homs as of this evening.” Their presence could discourage a resumption of regime shelling.

The advance team is to increase to 30 monitors next week, before the larger contingent arrives.

Under a preliminary agreement between the U.N. and the Syrian government, the enlarged mission will be able to walk and drive freely through the country. However, Syria has so far not agreed to a U.N. demand that observers use their own planes and helicopters, seen as a key to the mission’s success because it could reduce friction on the ground.

The challenges facing monitors became apparent this week when the advance team visited several hotspots. Large crowds of regime opponents surrounded the monitors, and government troops opened fire to disperse the protesters, in one instance while the observers were still present.

Reflecting concern about inadvertently setting off violence, the team decided not to go out on Friday, the main day for anti-government protests. The team leader, Col. Ahmed Himiche, said he and his men did not want to be “tools for escalation.”

Hilal Khashan, an analyst at the American University of Beirut, said he believes the regime will try to sabotage the larger mission because it could pose a threat.

The presence of observers “attracts large crowds and anti-regime demonstrations,” said Khashan. “If the observers spread throughout Syria, the extent of the protests will increase dramatically.”

Syria denies it is facing a popular uprising, claiming it is being targeted by a foreign-led conspiracy of criminals and terrorists. Ja’afari, the Syrian U.N. envoy, reiterated Saturday that the regime reserves the right to respond to “armed terrorist groups.”

Even Russia’s envoy appeared to be skeptical about the regime’s latest claims that it has pulled troops and tanks from Syria’s cities.

“If indeed this is the case, this is a very important step in implementation of the Kofi Annan plan,” said Russia’s U.N. ambassador, Vitaly Churkin.

___

Associated Press writer Edith M. Lederer at the United Nations and Bassem Mroue in Beirut contributed reporting.

Annan, joint emissary for the U.N. and the Arab League, was to travel to Doha, Qatar, on Tuesday to brief the Arab League on the situation in Syria.

Diplomats and finance ministry officials from the Arab world, the West and elsewhere also were meeting Tuesday in Paris to coordinate sanctions against the Assad regime. Diplomats say a string of EU, U.S. and other sanctions are affecting Assad by curbing Syria’s ability to export oil and the ability of his cronies to do business abroad.

A six-member advance team of U.N. observers arrived in Damascus over the weekend, but hasn’t traveled to hotspots yet. U.N. officials said the team is still devising a plan on where to go and whom to meet. A previous Arab League observer mission was hampered by regime restrictions on movement, and U.N. chief Ban Ki-moon has demanded his monitors be given free access.

In Damascus, the head of the observer team, Col. Ahmed Himmiche, suggested Tuesday it would take time to get to the hardest hit areas.

“There should be coordination and planning and we should move … step by step,” he said. “It’s not an easy process.”

The group is to be reinforced by an additional 25 monitors who are expected to arrive in the next few days, he said.

While the overall level of violence is down since the cease-fire formally took effect Thursday, the regime has stepped up attacks. The number of people killed every day has also risen steadily since a brief lull that coincided with the start of the truce. At least 26 people were reported killed on Monday.

In violence Tuesday, army tanks shelled the southern town of Busra al-Harir, killing at least two people, said the Britain-based Syrian Observatory for Human Rights, an activist group. The town, about 70 kilometers (45 miles) south of the capital of Damascus, is a stronghold of the rebel Free Syrian Army.

Regime forces also shelled the Khaldiyeh neighborhood in the central city of Homs, a center of the rebellion against Assad, according to the Observatory. Homs has been under continuous regime attack, with only a short break on the first day of the cease-fire, activists said.

The regime appeared to be pushing to take control of the last rebel-held districts in Homs, said activists in the city. Khaldiyeh was shelled from three sides on Monday, and half of the nearby district of Bayada fell under the army’s control over the weekend. Activists said Monday that the Free Syrian Army was holding its ground in the Qarabees and Jouret al-Shayah neighborhoods.

On Monday, at least five people were killed in Homs shelling, the Observatory said. Across Syria, at least 26 people were killed Monday, including 10 in a daylong gunbattle between rebel fighters and the Syrian army in the northwestern town of Idlib, the group said.

Another activist group, the Local Coordination Committees, said at least 55 people were killed Monday, including 26 in Idlib.

Hamas spokesman Fawzi Barhoum told The Associated Press that the group has only “humble weapons that aim to defend and not to attack.” This limited arsenal “does not give us the ability to be part of any regional war,” he said. Salah Bardawil, a member of Hamas’ top decision-making body, the political bureau, reportedly adopted a similar view.

Later Wednesday, Iran’s semi-official Fars news agency quoted another senior Hamas official in Gaza, Mahmoud Zahar, as saying that “retaliation with utmost power is the position of Hamas with regard to a Zionist war on Iran.” Zahar could not be reached for comment Wednesday evening.

There have been increasing signs of rifts in Hamas, including between Gaza strongmen like Zahar and leaders in exile who advocate a more pragmatic line. It’s not clear who will prevail, including on ties with Iran.

Israel believes Iran is trying to produce nuclear weapons, while Iran insists its nuclear program is for peaceful purposes. Israel has been hinting at a military strike.

President Barack Obama told Netanyahu at the White House that diplomacy and sanctions must be given more time, but he did not rule out military action if necessary to protect U.S. interests.

Israeli military officials have said that in the event of Israel-Iran hostilities, Tehran’s proxies on Israel’s borders — Hamas in the Gaza Strip and Hezbollah in Lebanon — could open fire at Israel. Israel’s military intelligence chief has warned that Israel’s enemies have about 200,000 rockets and missiles that could strike all parts of the country.

Hamas has a long history of attacks on Israel, including suicide bombings and thousands of rockets and mortars fired from the Gaza Strip over the past decade.

In its 24-year existence, Hamas has also stayed out of other conflicts, saying its sole purpose is to shake off Israel’s occupation of Palestinian lands. Hamas does not accept Israel’s existence.

In recent months, Hamas has distanced itself from longtime allies Iran and Syria, mainly over Syrian President Bashar Assad’s brutal crackdown on regime opponents, but it has not cut ties with Iran, which provides Hamas with vital funding.

Hamas has largely observed an informal truce with Israel since suffering heavy losses during an Israeli military offensive in Gaza three years ago. The group does not want to provoke another round of heavy fighting, though it has done little to stop militants from smaller groups from firing rockets and mortars into Israel.

Hezbollah has also been unclear on how it would respond to an Israeli strike on Iran. Last month, Hezbollah chief Hassan Nasrallah said Iran would not ask Hezbollah to retaliate.

“There is speculation about what would happen if Israel bombed Iran’s nuclear facilities,” Nasrallah said at the time. “I tell you that the Iranian leadership will not ask Hezbollah to do anything. On that day, we will sit, think and decide what we will do.”

In 2006, Hezbollah and Israel fought a 34-day war that killed about 1,200 people in Lebanon and 160 in Israel. Hezbollah fired nearly 4,000 rockets at Israel.

In Israel Wednesday, Netanyahu’s national security adviser, Yaakov Amidror, welcomed an upcoming round of talks between six world powers and Iran over its suspect nuclear program. No date has been set.

Amidror said Iran can be prodded into concessions only by the threat of military action, and that there is a chance the talks might fail.

“Without a real military alternative, the Iranians will not make concessions in the talks,” he said.

Israel believes Iran is trying to produce nuclear weapons, while Iran insists its nuclear program is for peaceful purposes. President Barack Obama told Netanyahu at the White House that diplomacy and sanctions must be given more time, but he did rule out military action if necessary to protect U.S. interests.

Israeli military officials have said that in the event of Israel-Iran hostilities, Tehran’s proxies on Israel’s borders — Hamas in the Gaza Strip and Hezbollah in Lebanon — could open fire at Israel. Israel’s military intelligence chief has warned that Israel’s enemies have about 200,000 rockets and missiles that could strike all parts of the country.

Asked about a possible Hamas attack on Israel, Barhoum said the Hamas arsenal is limited.

“Hamas weapons and the weapons of the Palestinian resistance, in general, are humble weapons that aim to defend and not to attack, and they are to defend the Palestinian people,” he told The Associated Press. “That does not give us the ability to be part of any regional war.”

In defense of Hamas’ patron, he added, “The world shouldn’t stand idly by concerning the Zionists’ intention to attack Iran. This war is a danger to world peace.”

Hamas has a long history of attacks on Israel, including suicide bombings and thousands of rockets and mortars fired from the Gaza Strip over the past decade. Hamas continues to smuggle weapons, including longer-range missiles, into Gaza through tunnels under its southern border with Egypt.

In its 24-year existence, Hamas has also stayed out of other conflicts, saying its sole purpose is to shake off Israel’s occupation of Palestinian lands. Hamas does not accept Israel’s existence.

In recent months, Hamas has distanced itself from longtime allies Iran and Syria, mainly over Syrian President Bashar Assad’s brutal crackdown on regime opponents.

Iran repeatedly urged the Hamas leadership in exile, based in the Syrian capital of Damascus, to side publicly with Assad. Hamas refused, and its top leaders have left Damascus in recent months, seeking refuge in Qatar, Egypt, Turkey and other countries in the region.

At the same time, Hamas has been careful not to cut ties with Iran, since it still relies on financial support from Tehran. Hamas needs those funds to help maintain its government in the Gaza Strip, a territory it seized by force in 2007.

Hamas has largely observed an informal truce with Israel since suffering heavy losses during an Israeli military offensive in Gaza three years ago. The group does not want to provoke another round of heavy fighting, though it has done little to stop militants from smaller groups from firing rockets and mortars into Israel.

Hezbollah has been less clear on how it would respond to an Israeli strike on Iran. Last month, Hezbollah chief Hassan Nasrallah said Iran would not ask Hezbollah to retaliate.

“There is speculation about what would happen if Israel bombed Iran’s nuclear facilities,” Nasrallah said at the time. “I tell you that the Iranian leadership will not ask Hezbollah to do anything. On that day, we will sit, think and decide what we will do.”

In 2006, Hezbollah and Israel fought a 34-day war that killed about 1,200 people in Lebanon and 160 in Israel. Hezbollah fired nearly 4,000 rockets at Israel.

In Israel Wednesday, Netanyahu’s national security adviser, Yaakov Amidror, welcomed an upcoming round of talks between six world powers and Iran over its suspect nuclear program. No date has been set.

Amidror said Iran can be prodded into concessions only by the threat of military action, and that there is a chance the talks might fail.

“Without a real military alternative, the Iranians will not make concessions in the talks,” he said.

Israel believes Iran is trying to produce nuclear weapons, while Iran insists its nuclear program is for peaceful purposes. President Barack Obama told Netanyahu at the White House that diplomacy and sanctions must be given more time, but he did rule out military action if necessary to protect U.S. interests.

Israeli military officials have said that in the event of Israel-Iran hostilities, Tehran’s proxies on Israel’s borders — Hamas in the Gaza Strip and Hezbollah in Lebanon — could open fire at Israel. Israel’s military intelligence chief has warned that Israel’s enemies have about 200,000 rockets and missiles that could strike all parts of the country.

Asked about a possible Hamas attack on Israel, Barhoum said the Hamas arsenal is limited.

“Hamas weapons and the weapons of the Palestinian resistance, in general, are humble weapons that aim to defend and not to attack, and they are to defend the Palestinian people,” he told The Associated Press. “That does not give us the ability to be part of any regional war.”

In defense of Hamas’ patron, he added, “The world shouldn’t stand idly by concerning the Zionists’ intention to attack Iran. This war is a danger to world peace.”

Hamas has a long history of attacks on Israel, including suicide bombings and thousands of rockets and mortars fired from the Gaza Strip over the past decade. Hamas continues to smuggle weapons, including longer-range missiles, into Gaza through tunnels under its southern border with Egypt.

In its 24-year existence, Hamas has also stayed out of other conflicts, saying its sole purpose is to shake off Israel’s occupation of Palestinian lands. Hamas does not accept Israel’s existence.

In recent months, Hamas has distanced itself from longtime allies Iran and Syria, mainly over Syrian President Bashar Assad’s brutal crackdown on regime opponents.

Iran repeatedly urged the Hamas leadership in exile, based in the Syrian capital of Damascus, to side publicly with Assad. Hamas refused, and its top leaders have left Damascus in recent months, seeking refuge in Qatar, Egypt, Turkey and other countries in the region.

At the same time, Hamas has been careful not to cut ties with Iran, since it still relies on financial support from Tehran. Hamas needs those funds to help maintain its government in the Gaza Strip, a territory it seized by force in 2007.

Hamas has largely observed an informal truce with Israel since suffering heavy losses during an Israeli military offensive in Gaza three years ago. The group does not want to provoke another round of heavy fighting, though it has done little to stop militants from smaller groups from firing rockets and mortars into Israel.

Hezbollah has been less clear on how it would respond to an Israeli strike on Iran. Last month, Hezbollah chief Hassan Nasrallah said Iran would not ask Hezbollah to retaliate.

“There is speculation about what would happen if Israel bombed Iran’s nuclear facilities,” Nasrallah said at the time. “I tell you that the Iranian leadership will not ask Hezbollah to do anything. On that day, we will sit, think and decide what we will do.”

In 2006, Hezbollah and Israel fought a 34-day war that killed about 1,200 people in Lebanon and 160 in Israel. Hezbollah fired nearly 4,000 rockets at Israel.

In Israel Wednesday, Netanyahu’s national security adviser, Yaakov Amidror, welcomed an upcoming round of talks between six world powers and Iran over its suspect nuclear program. No date has been set.

Amidror said Iran can be prodded into concessions only by the threat of military action, and that there is a chance the talks might fail.

“Without a real military alternative, the Iranians will not make concessions in the talks,” he said.