Tripoli: Libya could descend into civil war if Muammar Gaddafi refuses to quit, the United States said on Tuesday, its demand for his departure carrying fresh weight after news of Western military preparations.
But the veteran Libyan leader remained defiant, sending forces to a western border area amid fears that the most violent Arab revolt may grow bloodier and spark a humanitarian crisis.
His most prominent son, Saif al-Islam, warned the West against launching any military action to topple his father, and said the veteran ruler would not go into exile or step down.
"Using force against Libya is not acceptable, there`s no reason, but if they want ... we are ready, we are not afraid," he told Sky television, adding: "We live here, we die here."
In Moscow, a Kremlin source suggested Gaddafi should step down, calling him a "living political corpse who has no place in the modern civilized world," Interfax news agency reported.
In prepared testimony to lawmakers in Washington, Secretary of State Hillary Clinton said Libya could become a democracy or face a drawn-out civil war.
"In the years ahead, Libya could become a peaceful democracy or it could face protracted civil war," she said.
US Ambassador to the United Nations Susan Rice told US television networks Washington would keep pressure on Gaddafi until he steps down, while working to stabilize oil prices and avert a possible humanitarian crisis.
"We are going to keep the pressure on Gaddafi until he steps down and allows the people of Libya to express themselves freely and determine their own future," Rice told ABC television.
But Rice stopped short of saying the Obama administration was ready to impose a no-fly zone over Libya that would prevent Gaddafi from using aircraft against rebels fighting against him.
On Monday the United States said it was moving ships and planes closer to the country and British Prime Minister David Cameron said his government would work to prepare a "no-fly" zone to protect the Libyan people.
In Paris, French Foreign Minister Alain Juppe sounded a note of caution about Western military thinking on Libya, saying foreign military intervention in the oil-producing country would not happen without a clear United Nations mandate.
But Cameron, speaking in London on Tuesday, said the West was weighing its military options because it was not "acceptable to have a situation where Colonel Gadaffi can be murdering his own people using airplanes and helicopter gunships."
Gaddafi appeared unmoved by the outside pressure, and suspicions grew that the veteran leader, a survivor of numerous coup attempts during his rule, did not grasp the unprecedented scale of the forces now gathering against him.
"All my people love me," he told the US ABC network and the BBC on Monday, dismissing the significance of a rebellion against his rule that has ended his control over much of eastern Libya, the center of oil output.
Around the Libyan capital there were queues outside bread shops on Tuesday morning. Some residents said many bread shops were limiting the number of loaves customers could buy, forcing people to visit several to get needed supplies.
"The situation is nervous," said Salah, a 35-year-old doctor at one bread shop where about 15 people were queuing outside.
"Of course I am worried. My family is afraid. They are waiting at home. We have been hearing gun-fire.
"But the people are together. I hope the situation calms down. I am 35 and this is the first time I saw something like this in Libya. It is very scary."
A Tripoli resident said the main state television station, Jamahiriya, was no longer available on its usual satellite channel. He said Libiya, another of Libya`s three television stations, which are all state controlled, had told viewers Jamahiriya`s signal was being subjected to interference.
It was not clear if the interference was linked to a campaign, led by Libyan exile groups, to persuade satellite television operators to stop carrying Libyan television.
In the opposition bastion of Benghazi, residents said food and other necessities were in good supply despite the fact that many factories and shops had halted work since the revolt began.
Bank withdrawals were still limited and drivers said petrol, scarce a few days ago, had since returned to good supply.
"There have been no problems yet, the crisis is still fresh," said Hassan Ghorfany, 37, who works in a wholesale store selling food in Benghazi, adding that some but not all of his suppliers had stopped working.
Barely 12 hours later, Libyan forces re-asserted their presence at the remote Dehiba southern border crossing, decorating the border post with green Libyan flags.
The previous day, there was no Libyan security presence at the border crossing. Dehiba is about 60 km (40 miles) from the town of Nalut.
In another part of the west, residents said pro-Gaddafi forces deployed to reassert control of Nalut, about 60 km from the Tunisian border in western Libya, to ensure it did not fall into the hands of anti-Gaddafi protesters.
A resident of the northern town of Misrata, Mohamed, told Reuters by telephone: "We are preparing a mass demonstration for this afternoon at 16:30 (9:30 a.m. EST). The town is calm so far."
Misrata has been under the control of anti-Gaddafi rebels for several days, local people say. Witnesses have said that a unit of the paramilitary force led by Khamis Gaddafi, a son of Gaddafi, controls a part of a military airbase outside Misrata.
Despite his continued hold on Tripoli, his last remaining stronghold and home to more than 1.5 million people, Gaddafi`s power to influence events in his vast desert country has shrunk dramatically in the past two weeks.
Numerous tribal leaders, officials, military officers and army units have defected to the rebels, taking with them swathes of the country of six million including the energy-producing east. Sanctions will squeeze his access to funds.
In Geneva, Russian Foreign Minister Sergei Lavrov called on world powers to fully implement a UN Security Council resolution on Libya. The text, adopted on Saturday, includes a freeze on Muammar Gaddafi`s assets, travel ban and referring his regime`s brutal crackdown to the International Criminal Court.
In a potential blow to Gaddafi, Libya`s National Oil Corporation said Libya`s oil output had halved because of the departure of oil workers, although installations were undamaged and NOC was still overseeing Libya`s oil production and exports.
At Ras Jdir on the border with Tunisia, Tunisian border guards fired into the air to try to control a crowd of people clamoring to get through a frontier crossing to escape the violence in neighboring Libya.
Border guards were letting people, mostly foreigners who had been working in Libya, through the crossing at Ras Jdir but could not process them through immigration fast enough to keep up with the numbers arriving.
Tens of thousands of people, mostly migrant workers, have fled Libya since an uprising against Gaddafi led to a violent crackdown by his security forces. About 70,000 people have passed through the Ras Jdir border crossing in the past two weeks, and in the last few days the rate has increased to up to 15,000 per day, said Ayman Gharaibeh, an officer with the UN refugee agency.
Revolutions in neighboring Tunisia and Egypt have helped to ignite resentment of four decades of often bloody political repression under Gaddafi as well as his failure to use Libya`s oil wealth to tackle widespread poverty and lack of opportunity.
Fawaz Gerges, a Middle East expert at the London School of Economics, wrote that the major losers of the wave of Arab uprisings were "the autocratic rulers who have bled their societies dry, used blood and iron to suppress dissent, and neglected the hopes and aspirations of their citizens."