The U.S. military deployed naval and air units near Libya, and the West moved to send its first concrete aid to Libya's rebellion in the east of the country, hoping to give it the momentum to oust Moammar Gadhafi. But the Libyan leader's regime clamped down in its stronghold in the capital and appeared to be maneuvering to strike opposition-held cities.
In Washington, Defense Department spokesman Col. Dave Lapan said the naval and air forces were deployed to have flexibility as Pentagon planners worked on contingency plans, but did not elaborate. The U.S. has a regular military presence in the Mediterranean Sea.
The European Union slapped an arms embargo, visa ban and other sanctions on Libyan leader Moammar Gadhafi's regime, as British Prime Minister David Cameron told British lawmakers Monday he is working with allies on a plan to establish a military no-fly zone over Libya, since "we do not in any way rule out the use of military assets" to deal with Gadhafi's embattled regime.
In the most direct U.S. demand for Gadhafi to step down, Secretary of State Hillary Rodham Clinton said the Libyan leader must leave power "now, without further violence or delay."
France was sending two planes with humanitarian aid, including medicine and doctors, to Benghazi, the opposition stronghold in eastern Libya, French Prime Minister Francois Fillon said. That would be the first direct Western aid to the uprising that has taken control of the entire eastern half of Libya. Fillon said it was the start of a "massive operation of humanitarian support" for the east and that Paris was studying "all solutions" -- including military options.
The two sides in Libya's crisis appeared entrenched in their positions, and the direction the uprising takes next could depend on which can hold out longest. Gadhafi is dug in in Tripoli and nearby cities, backed by security forces and militiamen who are generally better armed than the military. His opponents, holding the east and much of the country's oil infrastructure, also have pockets in western Libya near Tripoli. They are backed by mutinous army units, but those forces appear to have limited supplies of ammunition and weapons.
In the two opposition-held cities closest to Tripoli -- Zawiya and Misrata -- rebel forces were locked in standoffs with Gadhafi loyalists.
An Associated Press reporter saw a large pro-Gadhafi force massed on the western edge of Zawiya, some 30 miles (50 kilometers) west of Tripoli, with about a dozen armored vehicles and tanks and jeeps mounted with anti-aircraft guns. An officer said they were from the elite Khamis Brigade, named after the Gadhafi son who commands it. U.S. diplomats have said the brigade is the best equipped force in Libya.
Residents inside the city said they were anticipating a possible attack.
"Our people are waiting for them to come and, God willing, we will defeat them," one resident who only wanted to be quoted by his first name, Alaa, told AP in Cairo by telephone.
In Misrata, Libya's third largest city 125 miles (200 kilometers) east of Tripoli, Gadhafi troops who control part of an air base on the city's outskirts tried to advance Monday. But they were repelled by opposition forces, who include residents armed with automatic weapons and army unites allied with them, one of the opposition fighters said.
He said there were no casualties reported in the clashes and claimed that his side had captured eight soldiers, including a senior officer.
The opposition controls most of the air base, and the fighter said dozens of anti-Gadhafi gunmen have arrived from further east in recent days as reinforcements.
Several residents of the eastern city of Ajdabiya said Gadhafi's air force also bombed an ammunition depot nearby held by the opposition. One, 17-year-old Abdel-Bari Zwei, reported intermittent explosions and a fire, and another, Faraj al-Maghrabi, said the facility was partially damaged. The site contains bombs, missiles and ammunition -- key for the undersupplied opposition military forces.
State TV carried a statement by Libya's Defense Ministry denying any attempt to bomb the depot. Ajdabiya lies about 450 miles (750 kilometers) east of Tripoli along the Mediterranean coast.
Gadhafi opponents have moved to consolidate their hold in the east, centered on Benghazi -- Libya's second largest city, where the uprising began. Politicians there on Sunday set up their first leadership council to manage day-to-day affairs, taking a step toward forming what could be an alternative to Gadhafi's regime.
The opposition is backed by numerous units of the military in the east that joined the uprising, and they hold several bases and Benghazi's airport. But so far, the units do not appear to have melded into a unified fighting force. Gadhafi long kept the military weak, fearing a challenge to his rule, so many units are plagued by shortages of supplies and ammunition.
Gadhafi supporters said Monday that they were in control of the city of Sabratha, west of Tripoli, which has seemed to go back and forth between the two camps the past week. Several residents told The Associated Press that protesters set fire to a police station, but then were dispersed. Anti-Gadhafi graffiti -- "Down with the enemy of freedom" and "Libya is free, Gadhafi must leave" -- were scrawled on some walls, but residents were painting them over.
In the capital, several hundred protesters started a march in the eastern district of Tajoura, which has been the scene of frequent clashes. After the burial of a person killed in gunfire last week, mourners began to march down a main street, chanting against the Libyan leader and waving the flag of Libya's pre-Gadhafi monarchy, which has become a symbol of the uprising, a witness said.
But they quickly dispersed once a brigade of pro-Gadhafi fighters rushed to the scene, scattering before the gunmen could fire a shot, the witness said. He and other residents in the capital spoke on condition of anonymity for fear of retaliation.
There were attempts to restore aspects of normalcy in the capital, residents said. Many stores downtown reopened, and traffic in the streets increased.
Tripoli was in turmoil on Friday, when residents said gunmen opened fire indiscriminately on protesters holding new marches. But since then, the capital has been quiet -- especially since foreign journalists invited by Gadhafi's regime to view the situation arrived Friday.
Long lines formed outside banks in the capital by Libyans wanting to receive the equivalent of $400 per family that Gadhafi pledged in a bid to shore up public loyalty.
One resident said pro-Gadhafi security forces man checkpoints around the city of 2 million and prowl the city for any sign of unrest. She told The Associated Press that the price of rice, a main staple, has gone up 500 percent amid the crisis, reaching the equivalent of $40 for a five-kilogram (10-pound) bag.
Bakeries are limited to selling five loaves of bread per family, and most butcher shops are closed, she said.
Some schools reopened, but only for a half day and attendance was low. "My kids are too afraid to leave home and they even sleep next to me at night," said Sidiq al-Damjah, 41 and father of three. "I feel like I'm living a nightmare."
Gadhafi has launched by far the bloodiest crackdown in a wave of anti-government uprisings sweeping the Arab world, the most serious challenge to his four decades in power. The United States, Britain and the U.N. Security Council all slapped sanctions on Libya this weekend.
In Geneva, U.S. Secretary of State Hillary Rodham Clinton was meeting Monday with foreign ministers from Britain, France, Germany and Italy, pressing for tough sanctions on the Libyan government. A day earlier, Clinton kept up pressure for Gadhafi to step down and "call off the mercenaries" and other troops that remain loyal to him.
"We've been reaching out to many different Libyans who are attempting to organize in the east and as the revolution moves westward there as well," Clinton said. "I think it's way too soon to tell how this is going to play out, but we're going to be ready and prepared to offer any kind of assistance that anyone wishes to have from the United States."
Two U.S. senators said Washington should recognize and arm a provisional government in rebel-held areas of eastern Libya and impose a no-fly zone over the area -- enforced by U.S. warplanes -- to stop attacks by the regime. But Fillon said a no-fly zone needed U.N. support "which is far from being obtained today."
Sabratha, 40 miles (65 kilometers) west of Tripoli -- a city known for nearby Roman ruins -- showed signs of the tug-of-war between the two camps. On Monday, when the journalists invited to Libya by the government visited, many people were lined up at banks to collect their $400. When they saw journalists, they chanted, "God, Moammar and Libya."
Ali Mohammed, a leader from the Alalqa tribe, the main tribe in the area, said in previous days Gadhafi opponents burned the main police station, an Internal Security office and the People's Hall, where the local administration meets. "I then held a meeting with the protesters to stop these acts the people said they will control their children and since then there has been no problems," he said.
"The thugs and rats were roaming the streets and they attacked the police station and then they disappeared," said resident Taher Ali, who was collecting his $400. "They are rats and thugs. We are all with Moammar."
An anti-Gadhafi activist in Sabratha told The Associated Press in Cairo by telephone that the opposition raided the police station and security offices last week for weapons, and had dominated parts of city. But then on Sunday, a large force of pro-Gadhafi troops deployed in the city, "so we withdrew," he said.
"The city is not controlled by us or them. There are still skirmishes going on," he said.
In Tripoli, a government spokesman blamed the West and Islamic militants for the upheaval, saying they had hijacked and escalated what he said began as "genuine" but small protests demanding "legitimate aand much needed political improvements."
"On one hand, Islamists love to see chaos ... this is paradise for them," he said. "The West wants chaos to give them reason to intervene militarily to control the oil."
"The Islamists want Libya to be their Afghanistan ... to complete their crescent of terror," he said. "This is not the first time the Islamic militants and the west find common cause."
AP correspondents Hamza Hendawi, Bassem Mroue and Ben Hubbard in Cairo, and Angela Charlton in Paris contributed to this report.