The UN-backed unity government based in Tripoli has announced the formation of a new military command to take charge of the battle against IS.

It has urged military forces to unite and not to launch any unilateral offensive on Sirte, the Mediterranean city which IS overran last June and has turned into a recruitment and training camp.

“We have finalised our preparations to retake Sirte and other regions and the military operation will begin soon,” a member of the new military command told AFP.

But in the east, the so-called Libyan Arab armed forces under the command of General Khalifa Haftar are also preparing for battle.

A spokesman for Haftar said military plans have been drawn up to “liberate Sirte” in an operation that will be launched from the Bamba region, east of second city Benghazi.

He said ground, air and naval forces would take part in the operation.

“We have the capability and the equipment,” he said, declining to give a date for the launch of the offensive or say how many forces will take part.

Mattia Toaldo, a policy fellow at the European Council on Foreign Relations, warned that separate attempts by the unity government and Haftar to wage war against IS could backfire.

“If pushed with uncoordinated efforts IS could either be in a better position to resist or decide to sneak out and move elsewhere,” he said.

He said the failure of Libya's armed forces to unite under one banner would create a new “military problem” and ultimately crush any hope of the unity government imposing its authority across the nation.

His comments come as IS jihadists have over the past week advanced from Sirte into territory held by the unity government, capturing key checkpoints along the Mediterranean coast.

- AFP