Replacing the heads of the heavily armed February 17 brigade and Rafallah al-Sahati militia would, if successfully implemented, effectively strip two of the most powerful men in eastern Libya of authority they had wielded with official permission but with virtually no control from the central government in Tripoli.

 In a move that follows other steps by the authorities to impose order on post-revolutionary armed groups in the wake of a fatal assault on the US consulate in Benghazi on Sept. 11, Colonel Salah Buhlaiga said two other colonels had been put in charge of the two groups.

"I led the negotiations and we have done it successfully," he told Reuters. "We have taken command of those two big militias."

The move was also confirmed by another colonel, Hamid Hanteesh, in the office of the army's chief of staff.

February 17, led until now by Fawzi Bukatif, and Rafallah al-Sahati, led by Ismail al-Sallabi, both maintain vast arsenals and jails where they hold prisoners outside of the state legal system.

Filling a security vacuum following the overthrow of Muammar Gaddafi a year ago, such groups have been allowed to operate with the consent of the authorities, but there has been a mounting public outcry for the government to place their fighters under full control of the regular army's chain of command.