Royal Air Force Typhoon FGR4s have joined forces with France's air force in a combined operation targeting an underground arms cache in Syria used by the IS group, according to the UK's MoD.
The site, identified by surveillance, was assessed as storing arms and explosives, the announcement noted, and was situated in hills just north of the ancient city of Palmyra in Syria's central region.
"Our aircraft used laser-guided Paveway IV weapons to strike a several access tunnels down to the depot... initial indications are that the target was engaged successfully," officials stated.
There was no sign of any civilian casualties in the strike late on Saturday and each participating jet returned to base without incident, the MoD added.
The British jets were supported by a Voyager refuelling tanker.
IS - also known as Daesh - established jihadist rule over parts of Syria and Iraq until 2019.
"This strike underscores our UK leadership, and determination to stand shoulder to shoulder with allied nations, to eliminate any revival of IS and their violent and radical beliefs in the area," Britain's Defence Chief the minister said.
British military aircraft have conducted overwatch operations over Syrian airspace to "forestall any attempted resurgence" of IS after its military defeat at the climactic battle in Baghuz in 2019, the MoD reported.
"I extend gratitude to all the members of the UK armed forces participating in this mission for their professionalism and their bravery," he said. "They were part of a great many British personnel on duty over the festive period. This operation, to take out dangerous terrorists who endanger our way of life, shows how UK forces are always on standby, continuously, ensuring Britain's security domestically and influential overseas."
In December, the American forces carried out what it called a "large-scale strike" targeting IS targets in Syria, after an assault killed two American soldiers and a civilian interpreter in the Palmyra area.
The UN reports Islamic State still boasts an estimated 5,000 to 7,000 fighters in Syria and Iraq.
