Libyan opposition forces fighting Muammar Gaddafi loyalists have formed a Union of Revolutionary Battalions, Arab media reported on Friday.
Field commanders from different parts of the country made the decision at a meeting in the city of Misrata.
The agreement will place hundreds of small armed groups operating across the country under a single command.
The decision came shortly after insurgent commanders east of Sirte, the biggest of the towns still outside their control, said they had postponed any offensive against the city for at least a week for lack of ammunition after heavy fighting.
Another reason they cited was there were many civilians still inside the city.
Sirte, Gaddafi's hometown, is besieged on three fronts by ruling National Transitional Council (NTC) forces.
NATO has extended its operations in Libya for another three months.
The NTC agreed on the makeup of an interim cabinet on Monday. NTC current chief Mahmoud Jibril has been named interim prime minister. There will be a total of 22 ministries in the new government.
Massive demonstrations against longtime leader Gaddafi broke out in Libya in mid-February. The international NATO-led military operation began on March 19 following a UN resolution on "targeted measures" to protect civilians.