The offshoot of Islamic State (Isis) in Libya is suspected of carrying out a car bomb attack killing five members of the military police with and wounding 14 near the western city of Khoms, some 120km east of the capital Tripoli.

The blast targeted the officials, aligned with the Libya Dawn alliance, which controls vast swathes western Libya and the area around Tripoli, at Khoms western checkpoint with Msallata. The checkpoint is a key strategic position held by Dawn forces on the coastal road between Misrata and Tripoli.

A Tripoli-based activist told IBTimes UK, speaking on condition of anonymity, that IS was expected to claim responsibility for the explosion within the coming hours. The militant group was responsible for a similar, recent car bomb attack in the town. Two weeks ago, three people were killed at an explosion at a checkpoint outside Khoms' air defence division.

The activist added that IS had been focusing more of its attacks against Khoms and Msallata in the wake of a botched prison break in September that left one of the group's senior leaders dead.

IS in Libya, which is split into eastern and western operational groups, has grown within the security vacuum created by Libya's 17-month-long civil war. The international community has put its faith in a unity government to address myriad problems the crisis in Libya has heaped on Europe's doorstep. The country's descent into chaos has fuelled the flow of migrants across the Mediterranean and given IS a launching pad to the continent.

Libya's paralysis has left IS knocking on the door of one of the most oil rich regions in northern Libya. At the beginning of October, IS killed one guard at Libya's Sidra oil terminal and injured two others. The oil port is the largest in Libya and has the potential to ship over 400,000 barrels of crude per day.

From its Sirte stronghold in central Libya, IS has launched tentative attacks across Libya's oil crescent. In March, IS militants kidnapped nine foreign oil workers and beheaded eight guards at al-Ghani oilfield.

Libya's central city of Misrata, one of the main military powers to emerge from the country's liberation war, made some abortive attempts to wrest control of Sirte from IS but a brutal crackdown by the militants in August on a local insurrection seems to have put the central city firmly within their control.