RAF Typhoon jets have conducted a mission with France's air force in a combined operation against an subterranean weapons facility in Syrian territory used by the Daesh militant organization, according to the UK Ministry of Defence.
The site, pinpointed through surveillance, was believed to be storing arms and explosives, the statement said, and was located in mountains just to the north of Palmyra in Syria's central region.
"The RAF jets employed Paveway IV guided bombs to strike a number of approach shafts leading to the facility... preliminary assessments indicate the strike was effective," the MoD said.
There was no sign of any harm to civilians in the strike late on Saturday and every plane involved made a safe return, the MoD added.
The Typhoon FGR4s were supported by a Voyager tanker plane.
IS - alternatively referred to as the so-called Islamic State - enforced jihadist rule over large swathes of Iraq and Syria until 2019.
"This strike shows British leadership, and determination to work closely with our allies, to eradicate any revival of the terrorist group and their violent and radical beliefs in the area," UK Defence Secretary John Healey remarked.
RAF aircraft have conducted patrols over Syria to "forestall any attempted comeback" of IS after its routing at the battle of Baghuz in 2019, the authorities noted.
"I must thank the personnel of our armed forces who took part in this mission for their skill and their courage," Healey added. "They were part of thousands of British troops deployed over the festive period. This action, to remove dangerous terrorists who endanger our security, demonstrates how British military are ready to step up, all year round, ensuring Britain's security domestically and influential overseas."
During December, the American forces executed what it described as a "large-scale strike" against IS targets in Syria, following an assault claimed the lives of two American soldiers and a civilian interpreter in the Palmyra area.
The U.N. estimates Islamic State still has between 5,000 and 7,000 combatants in Iraq and Syria.
