The rebels had previously announced his death twice since the start of the revolution.
In a separate development Algeria confirmed other members of the Gaddafi family have found refuge there. They include his wife, daughter, and two other sons.
Algeria's welcome for the Gaddafis was condemned.
"This is an act of aggression against the Libyan people and their wishes and aspirations. We will use all legal measures to extradite these criminals and put them on trial," said the Libyan National Transitional Council's Mahmoud Shammam.
The NTC also said every Gaddafi family member was wanted for financial crimes, and that they would be pursued and arrested anywhere.
Algeria is the only one of Libya's north African neighbours not to have recognised the NTC.
Late on Monday rebels also claimed to be "almost certain" they had killed intelligence chief Abdullah al-Senussi, who along with Muammar Gaddafi and son Saif al-Islam was wanted by the ICC on charges of crimes against humanity.
SOURCE: Euronews
