Gaddafi and his son Saif al-Islam, now in NTC custody, were indicted for crimes against humanity by the ICC [Reuters]

The death of former Libyan leader Muammar Gaddafi, who was captured and killed by fighters in October, may have been a war crime, the chief prosecutor of the International Criminal Court [ICC] has said.

Luis Moreno-Ocampo said on Thursday: "I think the way in which Mr Gaddafi was killed creates suspicions of ... war crimes. I think that's a very important issue."

Moreno-Ocampo's comments came a day after the former Libyan leader’s daughter, Aisha Gaddafi, called on the ICC to investigate the death of her father and brother at the hands of Libyan fighters.

The ICC prosecutor said he had sent a letter to the head of Libya’s ruling National Transitional Council [NTC] asking what the government's plans were to investigate alleged war crimes by all parties, including the rebels.

Moreno-Ocampo, referring to the Rome statute that established the war crimes tribunal, said the ICC would step in only if Libyan authorities were unwilling or unable to act.

Under pressure from Western allies, the NTC has promised to investigate how Gaddafi and his son Motassim were killed.

Saif al-Islam's case

The uprising against Gaddafi's 42-year rule erupted in February, quickly escalated into civil war, and ended in October with the Libyan leader's capture and death in unclear circumstances.

Mobile phone footage showed both Gaddafi and his son alive after their capture. The former Libyan leader was seen being mocked, beaten and abused before he died, in what NTC officials said was crossfire.

The ICC prosecutor said his office was also working closely with Libyan authorities on the cases of Saif al-Islam, Gaddafi's once-influential son, and Abdullah al-Senoussi, his former intelligence chief, who were captured and face ICC charges of crimes against humanity for their roles in the uprising.

He said the Libyan government must tell the court by January 10 whether they would hand over Saif. Investigators from the tribunal were in Libya last week to pursue the inquiry.

Libyan authorities say they plan to try him in Libya instead of handing him over to The Hague-based ICC.

The UN Security Council referred Gaddafi's crackdown on pro-democracy demonstrators to the ICC in February and authorised military intervention to protect civilians in March.