Isil fighters who have been routed from their former stronghold of Sirte in Libya could try to enter Europe by hiding among migrants heading across the Mediterranean in smugglers’ boats, Italy has warned.

Hundreds of Islamic State of Iraq and the Levant (Isil) fighters are fleeing Sirte after coming under sustained assault by Libyan ground forces and air strikes by US fighter jets and drones.

There is now a much greater risk that some terrorists could attempt to pass themselves off as migrants or refugees, according to the head of the parliamentary committee that oversees the Italian intelligence services.

If they were successful in reaching Italy, the Isil members could plan attacks on targets in Europe.