150 IS fighters killed in Syria strikes

The US-led coalition against Islamic State says it has killed up to 150 militants in air strikes on a headquarters in Syria.

The US-led coalition killed approximately 150 Islamic State fighters in an airstrike, Colonel Ryan Dillon, a spokesman for the coalition, says.

The target of Saturday's airstrike was an "ISIS headquarters and command and control centre," Dillon told CNN.

He said the strike involved "over a week's worth" of intelligence work involving multiple kinds of coalition intelligence as well as information from US-backed Syrian Democratic Forces fighting IS on the ground.

A statement from the coalition said the location was "exclusively" occupied by IS fighters and was under constant surveillance, ruling out the possibility of civilian casualties.

There was no confirmation of the attack from IS or its supporters.

The coalition says the group has lost 98 per cent of the territory that it seized across Iraq and Syria in 2014, when it proclaimed the creation of a "caliphate".