Islamic State (IS) militants have effectively taken over former dictator Muammar Gaddafi’s home city of Sirte in Libya as they exploit a civil war between two rival governments to expand in North Africa.

“Every night they open fire on us,” said Mohammed Abu Shebar, a guard at his frontline post, who with comrades on Sirte’s western outskirts holds the last position of troops belonging to one of the two warring Libyan governments, the General National Congress, which controls the capital Tripoli and most of the west of the country.

“They are only active at night,” he said, pointing to the militants’ position in a house just down the road blocked by sandbags.

IS have claimed a major city in the centre of Libya

Libya, which has descended into near anarchy since Nato warplanes helped rebels overthrow Gaddafi in a 2011 civil war, is now the third big stronghold for the Sunni Islamist group, also known as Isil or Isis, which declared a Caliphate to rule over all Muslims from territory it holds in Syria and Iraq.

Islamic State fighters became a major force last year in Derna, a jihadi bastion in Libya’s east, and quickly spread to the biggest eastern city Benghazi, where they have conducted suicide bombings on streets divided among armed factions.

By occupying Sirte over the past four months they have claimed a major city in the centre of the country, astride the coastal highway that links the east and west.

In Libya, the group deploys locally-recruited fighters, led by envoys sent from Syria and Iraq. They include Libyans returned from fighting on Syrian and Iraqi frontlines, steeped in the group’s ethos of extreme violence and permanent warfare between those it considers true Sunni Muslims and all others. Their gains in Libya, just across the sea from Italy, are worrying European governments and north African neighbours.