Four members of military forces loyal to Libya’s new U.N.-backed unity government have been killed and 30 wounded in clashes with ISIS militants near the western Libyan city of Misrata, a hospital spokesman said on Thursday.

Aziz Issa said the fighting was going on east of Assdada, around 80 km (50 miles) south of Misrata and the line of defense for brigades from the coastal city since ISIS militants seized several villages and checkpoints in the area late last week.

Assdada is also more than 150 km (90 miles) west of Sirte, ISIS’s stranglehold in the widely lawless North African country since last year.

The largest of the Misrata-based brigades support the unity government that is now gradually trying to stamp its authority on the country beyond its base in the capital Tripoli.

Commanders of an operations room set up by unity government authorities in Misrata say they are preparing an offensive to recapture Sirte. After several days of calm, fighting broke out at Assdada late on Wednesday.

European powers and the United States hope the unity government will be able to unite Libya’s rival political and armed factions to take on the extremist group.

ISIS controls a strip of more than 250 km (155 miles) of Libya’s central Mediterranean coastline, from which it has launched attacks to the east, west and south.

The hardliners have taken advantage of the political turmoil and security vacuum taking over the country after the uprising that overthrew Muammar Gaddafi five years ago to build a power base in Libya.