Tripoli: Libya on Wednesday marked the first Eid-ul-fitr feast in 42 years free of Moammar Gaddafi's yoke, as rebels proclaimed a "right to kill" the fugitive strongman and gave his forces three days to surrender.

Tens of thousands of people gathered at Tripoli's landmark Martyrs' Square to mark the start of the Muslim three-day holiday that follows the end of the fasting month of Ramadan, kneeling in prayer as they rejoiced in the collapse of Gaddafi's rule.

Men, women and children poured from dawn into the seafront site -- formerly known as "Green Square" -- decked out in their holiday best, as women ululated in triumph and spontaneous cries of joy erupted.

"This is the best holiday of my life," said Adel Masmoudi, who at 41 was born the year Gaddafi seized power.

An imam leading the prayer at the square urged all Libyans to stand united and hailed the ouster of "the tyrant Gaddafi", prompting jeers from the crowd at the mention of the fallen strongman's name.

With most of Libya overrun by NATO-backed rebel fighters, and Gaddafi's wife, daughter and two sons taking shelter in neighbouring Algeria, the whereabouts of the 69-year-old strongman himself however remained a mystery.

Omar Hariri, head of the rebels' military affairs, said believed Gaddafi had not left the country.

"The information I have is this: it is 80 per cent certain that Gaddafi is still in Libya," Hariri told AFP in Tripoli, adding that rebels suspected he is hiding either in Bani Walid, southeast of Tripoli, or in the outskirts of the capital.

Tags: Libya eid, Libya rebels, Martyrs' Square, Moammar Gaddafi, Omar Hariri, tripoli