Libyan Prime Minister Abdul Hamed Dbeibah said the security forces that fought in southern Tripoli a few days ago "must be punished".
"These actions are unacceptable and those who contributed to their eruption must be punished," Dbeibah said during a meeting on Saturday with senior security and military officials of his government in the capital Tripoli.
The Prime Minister issued orders to form a fact-finding committee that would present its findings in a week, so that necessary decisions can be made in this regard, Xinhua news agency reported.
Clashes between two government security forces erupted on the night of September 2 near a military camp in southern Tripoli, with unknown casualties.
The following day, the Presidency Council of Libya ordered an immediate cease-fire and the return of all fighting forces to their headquarters.
The UN Support Mission in Libya has expressed concern over the clashes, calling for an immediate cessation of hostilities and urging all parties to exercise maximum restraint.
Libya has been suffering insecurity and chaos ever since the fall of its leader Muammar Gaddafi in 2011.