Royal Air Force Typhoon jets have joined forces with France's air force in a joint strike on an underground arms cache in Syria operated by the IS group, according to the UK's MoD.
The site, identified by intelligence, was assessed as containing munitions and bombs, the release indicated, and was located in mountainous terrain just to the north of the ancient city of Palmyra in the heart of Syria.
"The RAF jets employed laser-guided Paveway IV weapons to strike a number of entry passages providing entry to the depot... early reports indicate the strike was effective," the MoD said.
There was no evidence of any harm to civilians in the attack on Saturday evening and each participating jet returned safely, the MoD added.
The British jets were supported by a Voyager refuelling tanker.
IS - also known as ISIS - imposed militant control over significant areas in both Syria and Iraq before its territorial defeat in 2019.
"This strike underscores the UK's leading role, and resolve to operate in unison with our allies, to stamp out any revival of IS and their violent and radical beliefs in the Middle East," the British Defence Secretary the Defence Secretary stated.
UK warplanes have carried out overwatch operations over Syria to "prevent any efforts to regroup" of Islamic State after its defeat at the battle of Baghuz in the year 2019, the MoD reported.
"I must thank all the members of our armed forces participating in this mission for their skill and their courage," he said. "They were part of a great many British personnel deployed over the festive period. This operation, to remove terrorist threats who threaten our security, highlights how our armed forces are always on standby, all year round, protecting the UK at home and strong abroad."
Last December, the United States armed forces conducted what it described as a "major assault" on Islamic State objectives in Syria, following an assault claimed the lives of two US troops and a local interpreter in Palmyra.
The United Nations reports Daesh still has an estimated 5,000 to 7,000 fighters in both countries.
