Amid the crackdown, a defiant Gadhafi appeared on state TV in the early hours Tuesday to show he was still in charge, brandishing a large umbrella and wearing a cap with fur ear flaps, and denying reports he had left the country.
The eruption of turmoil in the capital after a week of protests and bloody clashes in Libya's eastern cities has sharply escalated the challenge to Gadhafi, and his regime has been hit by a string of defections by ambassadors abroad and even some officials at home. His security forces have unleashed the bloodiest crackdown of any Arab country against the wave of protests sweeping the region, which toppled leaders of Egypt and Tunisia.
The U.N. Office of the High Commissioner for Human Rights, citing sources inside the country, said Tuesday that at least 250 people have been killed and hundreds more injured in the crackdown on protesters in Libya, though its officials said the true number was not known.
New York-based Human Rights Watch has put the toll at at least 233 killed, based on contacts with Libyan hospitals — but their toll did not include casualties from crackdowns in Tripoli since Sunday night, a sign of the difficulty of getting information out of the highly closed North African Nation.
The head of the U.N. agency, Navi Pillay, called for an investigation, saying widespread and systematic attacks against the civilian population "may amount to crimes against humanity."
The first major protests to hit an OPEC country — and major supplier to Europe — sent oil prices soaring to more than $93 a barrel Tuesday, and the industry has begun eyeing reserves touched only after Hurricane Katrina in 2005 and the 1991 Gulf War.
World leaders also have expressed outrage. U.S. Secretary of State Hillary Rodham Clinton called on Gadhafi to "stop this unacceptable bloodshed" and said the world was watching the events "with alarm."
Italian Foreign Minister Franco Frattini, visiting Cairo, denounced the violence and called for dialogue. He said his country was worried about the "imminent danger of a civil war in Libya and the exodus of migrants to Italy." Libya, just across the Mediterranean from southern Italy, is a common departure point for Africans trying to reach Europe, and Italy has close cooperation with Gadhafi's regime on stopping migrants, as well as economic ties.
Protesters demanding Gadhafi's ouster had planned a new rally in Tripoli's central Green Square and other locations Monday evening. But pro-regime militiamen — reportedly a mix of Libyans and foreign mercenaries — fanned out to unleash a heavy crackdown, sealing off neighborhoods and shooting from rooftops, several residents said.
Throughout the night, until just before dawn Tuesday, militiamen assaulted the Tripoli district of Fashloum, an impoverished area where many protesters have come, one resident told The Associated Press.
Militiamen shot any "moving human being" with live ammunition, including ambulances, so wounded were left in the streets to die, the resident said.
He said that as he fled the neighborhood Monday night, he ran across a group of militiamen, including foreign fighters. "The Libyans (among them) warned me to leave and showed me bodies of the dead and told me: 'We were given orders to shot anybody who moves in the place,'" said the resident.
"Bodies are now in the streets; those injured and now bleeding can't find a hospital or an ambulance to rescue them. Nobody is allowed to get in and if anybody gets in, will be shot to death," he said.
Like others reached in Libya he spoke on condition of anonymity because of fear of retaliation. Western media are largely barred from Libya and the report couldn't be independently confirmed.
Another resident said commandos were in control of the streets and were stationed on rooftops, opening fire. "Life is paralyzed, even those who were shot can't go to hospital," he said. "No one is able to walk in the street."
Mohammed Ali, an exile opposition activist, said he had also received reports from residents of scores of bodies in the streets. Inhabitants of the capital of some 2 million people were staying home Tuesday after warnings by Gadhafi loyalists that anybody on the streets would be shot, said Ali, who is based in the Gulf emirate of Dubai.
The week of upheaval in Libya has weakened — if not broken for now — the control of Gadhafi's regime in parts of the east. Protesters in the country's second largest city Benghazi over the weekend overran police stations and security headquarters, taking control of the streets with the help of army units that broke away and sided with them.
Benghazi residents, however, remained in fear of a regime backlash. One doctor in the city said Tuesday many spent the night outside their homes, hearing rumors that airstrikes and artillery assaults were imminent. "We know that although we are in control of the city, Gadhafi loyalists are still here hiding and they can do anything anytime," he said.
A warplane bombed Monday near a military camp that protesters had overwhelmed and were looting for weapons outside the city of Ajdabiya, said one witness, Ahmed al-Zawi. He said he was among those who broke into the camp to seize ammunition, automatic weapons and grenades when the plane dropped a bomb, hitting an empty area nearby, causing no injuries.
"I think the pilot is a good man. He was given orders to bomb the camp but he didn't," al-Zawi said. "We needed the weapons to protect ourselves and the city from the mercenaries."
Ajdabiya, south of Benghazi, appeared to be largely under control of protesters, who formed watch groups to guard streets and entrances to the city. The two main local tribes, the Maghrabiya and Zawi, announced their support for the protesters, and tribal fighters were guarding nearby oil fields and refineries to prevent vandalism or looting, al-Zawi said.
Gadhafi, the longest serving Arab leader with nearly 42 years in power, appeared briefly on TV early Tuesday to dispel rumors that he had fled. Sitting in a car in front of what appeared to be his residence and holding an umbrella out of the passenger side door, he told an interviewer that he had wanted to go to the capital's Green Square to talk to his supporters gathered there, but the rain stopped him.
"I am here to show that I am in Tripoli and not in Venezuela. Don't believe those misleading dog stations," Gadhafi said, referring to the media reports that he had left the country. The video clip and comments lasted less than a minute.
Gadhafi appeared to have lost the support of at least one major tribe, several military units and his own diplomats, including Libya's ambassador in Washington, Ali Adjali. Deputy U.N. Ambassador Ibrahim Dabbashi accused Gadhafi of committing genocide against his own people in the current crisis. Two air force colonels flew their Mirage fighter jets to Malta and sought asylum.
U.N. Secretary-General Ban Ki-moon told reporters in Beverly Hills, California, on Monday described the crackdown as "a serious violation of international humanitarian law." The U.N. spokesperson's office said late Monday that the Security Council had scheduled consultations on the situation in Libya for Tuesday morning.
British Prime Minister David Cameron, visiting Egypt, called the crackdown "appalling."
The chaos engulfing the country prompted many foreigners to flee.
Italy's government on Tuesday dispatched an air force jet to Benghazi, Libya's second-largest city, to evacuate around 100 Italian citizens. Many countries had already urged their nationals to avoid nonessential travel to Libya, or recommended that those already there leave on commercial flights.
Benghazi's airport was closed, according to an airport official in Cairo.
Egyptian troops, meanwhile, have beefed up their presence on the border with Libya and set up a field hospital as thousands of Egyptians return home from Libya by land, according to an Egyptian security official, who spoke on condition of anonymity because he wasn't allowed to release the information.
Oil companies, including Italy's Eni, Royal Dutch Shell PLC and U.K.-based BP have also begun evacuating their expat workers or their families or both.
Jordanians who fled Libya gave horrific accounts of a "bloodbath" in Tripoli, saying they saw people shot, scores of burned cars and shops, and what appeared to be armed mercenaries who looked as if they were from other African countries.
Many billboards and posters of Gadhafi were smashed or burned along a road to downtown Tripoli, "emboldening" protesters, said a man who lives on the western outskirts of the capital.