BEIRUT (AFP) - More than 30 militants in the Islamic State in Iraq and Syria (ISIS) group were killed on Friday in air strikes on Syria by warplanes of the US-led coalition, the Syrian Observatory for Human Rights said.

"At least 30 jihadists, and certainly more, were killed in coalition raids on Friday against positions and depots sheltering military vehicles and tanks, east and west of the city of Raqa," the self-proclaimed ISIS capital, the Britain-based monitor said.

Observatory chief Rami Abdel Rahman said the vehicles and armour were destroyed at Abu Qobeih west of Raqa.

"There are major losses in the ISIS ranks," he said.

"The raids also targeted bases, checkpoints, a training camp and a prison in the Mankhar area east of Raqa."