British Air Force Typhoon jets have conducted a mission with French warplanes in a joint strike against an underground arms cache in Syria operated by the IS group, according to the UK Ministry of Defence.
The site, pinpointed through reconnaissance, was thought to be housing weapons and explosive materials, the statement said, and was positioned in hills just above Palmyra in Syria's central region.
"The RAF jets used Paveway IV guided bombs to strike a several entry passages providing entry to the site... preliminary assessments suggest the strike was effective," the ministry announced.
There was no indication of any harm to civilians in the operation late on Saturday and all the aircraft returned to base without incident, the MoD added.
The Typhoon FGR4s were assisted by a Voyager aerial refuelling aircraft.
IS - referred to as ISIS - established militant control over parts of Syria and Iraq until 2019.
"This strike underscores British leadership, and commitment to stand shoulder to shoulder with our allies, to eliminate any revival of IS and their violent and radical beliefs in the Middle East," Britain's Defence Chief the minister remarked.
RAF aircraft have performed surveillance missions over Syrian airspace to "forestall any attempted resurgence" of the group after its military defeat at the Baghuz confrontation in the year 2019, the authorities noted.
"I want to thank every member of our armed forces involved in this mission for their skill and their bravery," the Defence Secretary said. "Including them were thousands of UK service members deployed over the festive period. This operation, to eliminate terrorist threats who endanger our safety, highlights how our armed forces are always on standby, throughout the year, ensuring Britain's security domestically and strong abroad."
Last December, the United States armed forces conducted what it termed a "major assault" against Daesh sites in the country, following an attack killed two American soldiers and a civilian linguist in Palmyra.
The UN reports Islamic State still boasts between 5,000 and 7,000 fighters in both countries.
