Libyan officials say Islamic State fighters have attacked a checkpoint, killing five security forces in an attempt to clear the road linking the central city of Sirte with Benghazi in the east.
Salem Jathran, the mayor of Ajdabia, says the extremists attacked Friday near his city on the road leading to Tobruk.
Libya has slid into chaos since the 2011 overthrow and killing of longtime dictator Muammarr Gaddafi, who ruled the country for four decades. It is now bitterly divided between an elected parliament and government in the far eastern city of Tobruk, which has little power on the ground, and an Islamist militia-backed government in the west that has seized Tripoli.
An Islamic State affiliate has also emerged, battling both other jihadi groups and forces loyal to both governments.