Fears are mounting that Islamic State terrorists could destroy an ancient Roman site in Libya which they have seized in their march towards the capital Tripoli and move closer to the West, Italian and British media report.

ISIS fanatics travelling in 30 pick-up trucks stormed the coastal city on Wednesday night after three of their men were captured by a rival militia.

Black-clad militants overpowered residents and set up checkpoints in the city, which is just 50 miles from Tripoli, before successfully retrieving the three men.

There are now concerns that the priceless landmarks in the city, a Unesco world heritage site, will be destroyed by ISIS, including a 3rd-century Roman amphitheatre.

In Syria, the group has already blown up historic sites at the Unesco world heritage site in Palmyra, including temples, columns and sculptures which the Islamist group claims depict ‘false idols’.