SANAA, YEMEN - In a defiant speech on state television Tuesday, Libyan strongman Moammar Gaddafi rejected demands that he relinquish power, even as leaders of a popular revolt seized control in some areas and top officials resigned to protest attacks on civilians.

"I will not leave the country, and I will die as a martyr," Gaddafi, 68, said in the lengthy but disjointed address.

The Libyan leader, whose government has been weakened in recent days even as it has brutally cracked down on mass protests, also said "damn those who try to stir unrest." He blamed the six-day-old popular revolt on "mercenaries" and foreign influences.

With the United Nations convening an emergency meeting on Libya and the Arab League planning to weigh in as well, Gaddafi's vicious crackdown against demonstrators appeared to be fast eroding whatever support had existed for his government.

In Washington, Libya's ambassador to the United States announced he had decided to "resign from serving the current dictatorship." He called on the United States to "raise its voice very strongly" to help oust Gaddafi, who assumed power in a 1969 military coup.

"This regime is shaking, and this is the time to get rid of him," Ambassador Ali Suleiman Aujali said on ABC's "Good Morning America." "The people are being kill[ed] in a brutal way. The people, they are armless, and the regime, they have all kind of weapons."

On Capitol Hill, Sen. John F. Kerry (D-Mass.) said the Libyan government's violence was "beyond despicable" and called for international sanctions, including the immediate cessation of operations in Libya by U.S. and other foreign oil companies.

Aujali said anti-government activists have taken control in the eastern part of Libya, an oil-rich North African nation where dissent and free expression have long been prohibited. The western part of the country, including the capital, Tripoli, remain in Gaddafi's hands, he said.

"We need the world to stand up by us," Aujali told GMA host George Stephanopolous. "We have to support the Libyan people. The world must take an action."

At the border with Egypt Tuesday, "people's committees" were acting in the place of security personnel. Thousands of Egyptians and Libyans fled the country.

Ibrahim Dabbashi, Libya's deputy ambassador to the United Nations, accused Gaddafi of killing his own people and urged the international community to act against the regime. "Either he has to get out or the Libyan people will kick him out," Dabbashi said in an interview with the television network al-Jazeera. "It is the end of the game."

In Triopli, residents reported that a heavy overnight rain had calmed the situation down. But the capital remained chaotic and volatile, with residents saying a new round of mass demonstrations was planned.