US special forces carried out a secret raid in eastern Syria on Sunday, killing a number of fighters from Islamic State of Iraq and the Levant (Isil).

Commandos parachuted down from four helicopters around 2.30pm on Sunday, according to local activists.

They set up roadblocks around the town of al-Kubar, between the Isil-held cities of Deir Ezzor and the group’s de facto capital Raqqa.

At least 25 jihadists were killed in the two-hour operation, the UK-based Syrian Observatory for Human Rights monitor said.

It is not yet clear what their target was, but some local activists suggested the raid may have been a hostage rescue attempt.