Khamis Gaddafi, 28, was confirmed to be among the dead following a NATO air strike on a command centre in the western town of Zliten, a rebel spokesman told AFP, citing spies operating among Gaddafi's ranks.
"Overnight there was a aircraft attack by NATO on the Gaddafi operations room in Zliten and there are around 32 Gaddafi troops killed. One of them is Khamis," said Mohammed Zawawi, a spokesman for the United Revolutionary Forces.
Rebels said their own operations room in eastern Libya had also intercepted radio chatter indicating Gaddafi's son had been killed. There was no independent verification of his death, which has been rumoured a number of times during Libya's five month-long civil war. At the Naples headquarters of NATO's Libya operations, an official asked about the claim, said: "We're looking into it."
Khamis, who was trained at a Russian military academy, commands the eponymous and much-feared Khamis Brigade -- one of the Libyan regime's toughest fighting units. The strike appears to have come just hours after Tripoli took journalists on an escorted tour of the centre of Zliten, an effort to rubbish rebel claims the town was under attack.