Washington: The US-led coalition fighting the Islamic State (IS) in Syria has said it killed 150 terrorists in an air strike on the terror group’s headquarters.

Dillon said terrorists were massing for movement at the headquarters before it was hit

The strikes took place on Saturday in the Syrian town of Al-Shafah, located in the Middle Euphrates River Valley, an area where remnants of the IS continue to operate, CNN reported on Tuesday.

Colonel Ryan Dillon, a spokesman for the coalition, told the news network that the target of the strike was IS headquarters and command control centre.

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 the IS on the ground.

A US military official said the strike was carried out by US Navy F/A-18 jets and unmanned drone aircraft. The aircraft carrier USS Theodore Roosevelt is currently operating in the Gulf in support of strikes against the IS in Syria.

Dillon said terrorists were massing for movement at the headquarters before it was hit.

“The strikes underscore our assertion that the fight to liberate Syria is far from over,” said Major General James Jarrard, commander of the coalition’s Special Operations Joint Task Force in Syria.

Jarrard added that coalition troops and members of the Syrian Democratic Forces “are still finding, targeting and killing IS terrorists intent on keeping their extremist hold on the region”.

The coalition says the terrorist 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”.

The strike and Jarrard’s statement of support for the Syrian Democratic Forces came as Turkey launched its own military operation into Syria, targeting Kurdish YPG fighters in the Afrin area of the country.