British Air Force Typhoon jets have operated alongside French aircraft in a combined operation on an subterranean weapons facility in Syria employed by the IS group, according to the UK's MoD.
The facility, pinpointed through reconnaissance, was thought to be containing munitions and bombs, the statement said, and was positioned in mountainous terrain just north of Palmyra in the heart of Syria.
"The RAF jets employed precision-guided Paveway IV munitions to strike a several entry passages down to the site... initial indications are that the strike was effective," the MoD said.
There was no indication of any civilian casualties in the operation late on Saturday and every plane involved returned safely, the defence officials confirmed.
The Typhoon fighters were assisted by a Voyager refuelling tanker.
The Islamic State group - referred to as Daesh - established militant control over significant areas in Iraq and Syria until 2019.
"This operation demonstrates British leadership, and determination to stand shoulder to shoulder with our allies, to stamp out any re-emergence of the terrorist group and their dangerous and violent ideologies in the region," Britain's Defence Chief John Healey remarked.
UK warplanes have carried out surveillance missions over Syria to "deter any attempted comeback" of Islamic State after its military defeat at the battle of Baghuz in 2019, the MoD reported.
"I want to thank the personnel of the UK armed forces who took part in this strike for their skill and their bravery," Healey added. "They were part of thousands of UK service members on duty over Christmas and New Year. This operation, to eliminate terrorist threats who threaten our safety, shows how our armed forces are prepared to act, all year round, protecting the UK at home and powerful internationally."
Last December, the United States armed forces carried out what it called a "large-scale strike" on IS targets in the country, subsequent to an assault killed two American soldiers and a civilian interpreter in the Palmyra area.
The U.N. says Islamic State still boasts an estimated 5,000 to 7,000 militants in both countries.
