A Libyan former minister was killed in clashes between unity government forces and fighters of the Islamic State militant group in the Sirte area, the LANA news agency reported Sunday.

Mohammed Soualem, labour minister in Ali Zeidan's government from 2012 to 2014, "was directing military operations against IS" at the time, said the agency loyal to the North African country's new unity government.

He was killed in fighting in the Abu Grein area, 100 kilometres (60 miles) west of Sirte, the militant group's main stronghold in Libya and hometown of late dictator Muammar Gaddafi.

"The clashes cost the life of Commander Mohammed Soualem and wounded five fighters," LANA reported.

"Air units in support of this operation succeeded in destroying dozens of vehicles" used by IS "and wounded several" miliatns, it said.

Last Tuesday, forces loyal to the Government of National Accord said they had retaken the key town of Abu Grein from IS group.

GNA troops and forces of the rival government based in the east of the country and loyal to General Khalifa Haftar are engaged in a race to be first to eject IS group from Sirte, 400 kilometres east of Tripoli.

The rivalry between the two factions is a major cause of international concern which sees it as jeopardising anti-militant efforts.

The GNA, recognised by the international community and based in Tripoli for the past month and a half, is trying to assert its authority over a country plagued by divisions and the militant threat.