The international community meanwhile called on the longtime leader to step down as euphoric residents celebrated in the Green Square, the symbolic heart of the Gaddafi regime.
Rebel spokesman Mohammed Abdel-Rahman, who was in Tripoli, cautioned that pockets of resistance remained Gaddafi loyalists and that as long as Gaddafi remains on the run the "danger is still there."
The clashes broke out at Gaddafi's longtime command center known as Bab al-Aziziya early today when government tanks emerged from the complex and opened fire at rebels trying to get in, according to Abdel-Rahman and a neighbor. An AP reporter at the nearby Rixos Hotel where foreign journalists stay could hear gunfire and loud explosions from the direction of the complex.
Tripoli resident Moammar al-Warfali, whose family home is next to the compound, said there appeared to be only a few tanks belonging to the remaining Gaddafi forces that have not fled or surrendered.
"When I climb the stairs and look at it from the roof, I see nothing at Bab al-Aziziya," he said. "NATO has demolished it all and nothing remains." The Rixos also remained under the control of Gaddafi forces, with two trucks loaded with anti-aircraft machine guns and pro-regime fighters and snipers posted behind trees.
Rebels and Tripoli residents set up checkpoints elsewhere in the city.
Italian Foreign Minister Franco Frattini said "no more than 10, 15 percent of the city is still in the hands of the regime." He did not elaborate on how he came up with the figure.
State TV broadcast bitter audio pleas by Gaddafi for Libyans to defend his regime. Opposition fighters captured his son and one-time heir apparent, Seif al-Islam, who along with his father faces charges of crimes against humanity at the International Criminal Court in the Netherlands. Another son was under house arrest.
"It''s over, frizz-head," chanted hundreds of jubilant men and women massed in Green Square late yesterday, using a mocking nickname of the curly-haired Gaddafi. The revelers fired shots in the air, clapped and waved the rebels' tricolor flag. Some set fire to the green flag of Gaddafi's regime and shot holes in a poster with the leader's image.
But Gaddafi's defiance in a series of angry audio messages raised the possibility of a last-ditch fight over the capital, home to 2 million people. Gaddafi, who was not shown in the messages, called on his supporters to march in the streets of the capital and "purify it" of "the rats."
Government spokesman Moussa Ibrahim also claimed the regime has "thousands and thousands of fighters" and vowed: "We will fight. We have whole cities on our sides. They are coming en masse to protect Tripoli to join the fight." NATO officials promised warplanes from the alliance would continue to conduct regular patrols over Libya despite the latest rebel successes.