Libyan opposition leader Moustafa Abdel-Jalil said Thursday that the rebel forces' chief of staff Abdel Fattah Younes was dead, Xinhua reported.
The National Transitional Council (NTC) chairman Jalil told a press conference that supporters of Muammar Gaddafi were responsible for the death of Younes. Two other military leaders were also killed.
The NTC would hold a three-day mourning for the death of Younes, Jalil said in the reble's stronghold Benghazi.
The Libyan government in Tripoli has not commented on the statement of the NTC.