Ten members of forces allied to Libya’s unity government fighting the IS were killed on Thursday in a suicide car bombing.
The attack took place in Abu Grain, a location 140 km west of Sirte, and 100 km south of Misrata. Spokesperson of the anti-Islamists brigades, Rida Issa said on Thursday that the casualties were believed to include civilians and policemen.
The military command of the brigades also said that two other car bombings had been foiled inside Sirte on the same day.
Brigades from Misrata are leading the campaign to recapture Sirte and have engaged in fire fights with Islamic State since advancing to the edge of the city centre last week.
The Islamic State expanded into Libya in late 2014, taking full control of Sirte the following year and making it its most important base outside the Middle East.
The U.N.-backed Government of National Accord (GNA) is seeking to unite different political and armed factions to take on Islamic State and end the turmoil that has plagued Libya since Muammar Gaddafi was toppled in an uprising five years ago.