Embattled Libyan leader Moamar Gaddafi was out of sight as rebels took over Tripoli and arrested two of his sons, while world leaders urged the former strongman to go.

Libyan rebel leader Mustafa Abdel Jalil hailed the end of the four-decade "Gaddafi era" on Monday, but urged rebels fighters to respect the law and promised fair trials for members of Gaddafi's government.
"I call on all Libyans to exercise self restraint and to respect the property and lives of others and not to resort to taking the law into their own hands," Mr Jalil told a news conference in the eastern city of Benghazi aired by Al Jazeera television.
He congratulated the Libyan people "for this historic victory" and thanked NATO for its military support, while cautioning that "the real moment of victory is when Gaddafi is captured".
Mr Jalil said he hoped Gaddafi, who faces an arrest warrant issued by the International Criminal Court, would be "captured alive so that he will be given a fair trial".
Two of his sons, Seif Al-Islam and Mohammed have already been captured, and another son, Al-Mutassim, was reported by Al Arabiya TV to be in the Bab al-Azizya compound in Tripoli.
The Western-backed rebels, whose grip around Tripoli tightened over the past two weeks before a final offensive on Sunday, said they were still encountering pockets of resistance, particularly around the Bab al-Aziziyah compound.
Gaddafi has not been seen in public since mid-June. His foes speculate he may not be in the Libyan capital, or even in the country.
He broadcast three defiant audio messages on Sunday, vowing he would not surrender and urging the people of Tripoli to "purge the capital", even as rebel forces swept through Tripoli and took over the symbolic Green Square.
French foreign minister Alain Juppe, whose government has been in the forefront of the international effort to oust Gaddafi, said Paris did not know where he was.
British prime minister David Cameron said London had no confirmation of his whereabouts either, adding Gaddafi's regime is in "full retreat" and he should give up any hope he has of clinging on to power.
"Gaddafi must stop fighting, without conditions, and clearly show that he has given up any claim to control Libya," he said.
US president Barack Obama said Gaddafi's 42-year autocratic regime was at a "tipping point" and that the "tyrant" must go, adding a call for the rebels to respect human rights and move to democracy.
"The Gaddafi regime is showing signs of collapsing. The people of Libya are showing that the universal pursuit of dignity and freedom is far stronger than the iron fist of a dictator," Mr Obama said in a statement.
Swift transfer
The International Criminal Court (ICC) is seeking the transfer of Seif al-Islam to The Hague to face charges of crimes against humanity.
Spokesman Fadi El-Abdallah told AFP the court was discussing his transfer with the Libyan rebel NTC.
Earlier on Monday, the court's prosecutor Louis Moreno-Ocampo said Seif al-Islam, 39, was arrested and in detention, calling for his swift transfer.
"We hope he can soon be in The Hague" to face judgement, Mr Moreno-Ocampo said.
Seif al-Islam is accused together with his father of orchestrating a plan to put down the Libyan revolt by "any means necessary" since it was sparked in mid-February.
This included the murder of hundreds of pro-freedom Libyan protesters and injuring hundreds of others when security forces shot a crowds using live ammunition, as well as the arrest and torture of numerous others.
Before the revolt erupted, Seif al-Islam was increasingly seen as a successor to his father, despite publicly ruling out any dynastic ambitions in the north African country.