Royal Air Force Typhoon jets have conducted a mission with France's air force in a coordinated attack against an underground arms cache in Syria operated by the Islamic State group (IS), according to the UK's MoD.
The facility, pinpointed through intelligence, was assessed as containing munitions and bombs, the statement said, and was located in mountainous terrain just to the north of Palmyra in Syria's central region.
"Our fighter planes used laser-guided Paveway IV weapons to strike a series of access tunnels providing entry to the site... early reports suggest the strike was effective," the MoD said.
There was no indication of any civilian impact in the operation late on Saturday and every plane involved returned safely, the defence officials confirmed.
The Typhoon fighters were backed up by a Voyager tanker plane.
Daesh - alternatively referred to as ISIS - imposed extremist governance over parts of Iraq and Syria until 2019.
"This action underscores British leadership, and resolve to operate in unison with our allies, to eradicate any revival of Daesh and their dangerous and violent ideologies in the Middle East," Britain's Defence Chief John Healey stated.
RAF aircraft have carried out patrols over Syrian airspace to "forestall any attempted comeback" of IS following its routing at the climactic battle in Baghuz in 2019, the ministry said.
"I want to thank all the members of the UK armed forces participating in this mission for their professionalism and their valour," the Defence Secretary added. "Including them were thousands of British personnel deployed over the festive period. This action, to remove terrorist threats who threaten our way of life, demonstrates how British military are always on standby, all year round, ensuring Britain's security at home and powerful internationally."
In December, the United States armed forces conducted what it described as a "major assault" on Islamic State objectives in the country, after an ambush killed two US servicemembers and a local interpreter in Palmyra.
The United Nations estimates Islamic State still maintains roughly 5-7 thousand fighters in Syria and Iraq.
