Islamic State terrorists seized control yesterday of Sabratha, a Unesco world heritage site famed for its Roman treasures, to move within 50 miles of the Libyan capital, Tripoli.

Travelling in 30 pick-up trucks, the jihadists stormed the coastal city after three of their men were captured by a rival militia on Wednesday night. There are fears for the city’s priceless heritage, including a 3rd-century Roman theatre that is one the best preserved in the world.

Black-clad militants quickly set up checkpoints across the city, easily overpowering the residents. “There was no resistance. No one wanted to provoke them, so they set up their checkpoints and drove about town showing off their weapons,” one terrified resident said. “They wanted to show who really controls the town.”