The leader of Libya's National Transitional Council has declared Muammar Gaddafi's rule "at an end" as rebel fighters stream into Tripoli.
"God has chosen that Gaddafi end should be at the hands of these youth, so that they may join the Arab uprising. I declare that Gaddafi's rule is at end" Mustafa Abdul Jalil told a press conference in the eastern stronghold of Benghazi.
He said the Libyan leader would be given a fair trial "but I have no idea how he will defend himself against the crimes he has committed against the Libyan people and the world".
Rebels and Nato are unaware of Gaddafi's whereabouts, Jalil and Western leaders said on Monday, but heavy fighting was reported outside his compound in Tripoli.
Jalil also confirmed Gaddafi's sons Muhammad and Saif al-Islam had been captured by fighters, after a prosecutor at the International Criminal Court (ICC) said they had been detained.
The ICC said it would contact rebels to discuss the handover of Saif al-Islam, Gaddafi's eldest son, who is wanted for crimes against humanity.
The comments came after prime minister David Cameron insisted that Libya was on the road to "freedom and democracy" but warned there was no room for "complacency".
Libyan rebels have been met with little resistance as they flood into Tripoli, media outlets have reported, with some pro-Gaddafi forces surrendering.
But Sky News said clashes were being witnessed around Gaddafi's compound and the Rixos hotel, where many journalists are holed up.
It added that significant numbers of rebels had been killed in fighting.
Earlier Colonel Gaddafi earlier urged his supporters to take up arms against rebel "rats" as he continues to cling on to his 41-year reign.
Western leaders have called on the dictator to stand down to avoid further bloodshed, with Cameron urging Gaddafi to "give up any claim he has to control Libya"
"His regime is falling apart and in full retreat. Gaddafi must stop fighting, without conditions - and clearly show that he has given up any claim to control Libya," the prime minister said on Monday.
Franco Frattini, the Italian foreign minister, said Gaddafi's "time was up".
"The time is up. There is no alternative to surrendering and handing himself in to justice," he said.