One of Muammar Gaddafi's sons, Mo'tassim, has been killed by fighters from Libya's NTC while another, Saif Al-Islam, is trying to flee the fallen city of Sirte but is being surrounded, a senior NTC military official said.

"Mo'tassim was killed by the fighters. He was trying to fight back and he was resisting them," National Transitional Council official Abdel Majid Mlegta told Reuters.

"Saif Al-Islam is trying to flee Sirte in a small convoy. Our fighters are encircling them," he added.

Libya's de facto prime minister Mahmoud Jibril also said Saif had been tracked down near the city of Sirte and that his convoy was under attack.

"We confirm that all the evils, plus Gaddafi, have vanished from this beloved country. I think it's for the Libyans to realise that it's time to start a new Libya, a united Libya, one people, one future," he said.

He also called on neighbouring Algeria to hand over members of Gaddafi's family who fled there in August. Two of Gaddafi's sons, his daughter and his wife are in Algeria. -Reuters