AFP, Tripoli :The Islamic State group carried out three suicide car bombings Sunday against forces allied with Libya’s unity government battling to retake the city of Sirte, an official said.”Three explosions from cars driven by Islamic State suicide bombers targeted our forces in Sirte,” Rida Issa, a spokesman for the unity government’s forces, told AFP.”There are several wounded among our forces,” he said, without providing further details.One bomber blew up his car a few metres (yards) from a group of pro-government fighters near the Abu Hadi roundabout in the city’s southeast, Issa said.The other bombers targeted pro-government forces and a field hospital in the city’s west.Forces loyal to the unity government have been fighting deadly street battles to retake Sirte, a coastal city 450 kilometres (280 miles) east of Tripoli that IS seized last year and turned into its main North African bastion.The loss of Sirte, former dictator Moamer Kadhafi’s home town, would be a major blow to IS at a time when it is under mounting pressure in Syria and Iraq.Brigades largely composed of fighters from Misrata advanced this week to the perimeter of Sirte’s city center, after launching a counter attack against Islamic State last month and driving the militant group back along the coastal road between the two cities.The brigades are part of an operation backed by Libya’s U.N.-backed Government of National Accord (GNA), which arrived in Tripoli in March and has been gradually working to establish its authority.Western powers see it as the best bet for trying to unite Libya’s political and armed factions against Islamic State and for restoring some stability to the oil-rich North African country.A source from the operations room in Misrata said fighters from the front line in the south of Sirte had looped round to the seafront to capture the port, which lies about 5 km (3 miles) east of the city center.The brigades have advanced more swiftly than many expected, though their progress has been hampered by suicide bombers, mines and snipers.Clashes in Sirte on Friday left 11 brigade members dead and 35 wounded, the operations room source said. More than 100 fighters from the GNA-backed brigades have been killed and more than 500 wounded since the campaign to recapture Sirte began in early May.Islamic State started expanding into Libya in 2014 as the political turmoil and conflict in the country worsened. It took full control of Sirte last year, but has struggled to retain territory or win support elsewhere in Libya.As the brigades based in Misrata have advanced on Sirte from the west, a separate force that controls some of Libya’s key oil terminals and is also aligned with the GNA has pushed Islamic State back from the east. They reached Harawa, a town about 70 km from Sirte, on Thursday.