Royal Air Force Typhoon jets have operated alongside France's air force in a combined operation against an underground arms cache in Syria employed by the IS group, according to the UK's MoD.
The location, pinpointed through surveillance, was thought to be containing munitions and bombs, the statement said, and was positioned in mountains just to the north of the ancient city of Palmyra in Syria's central region.
"The RAF jets employed Paveway IV guided bombs to target a series of access tunnels providing entry to the site... initial indications are that the target was engaged successfully," the MoD said.
There was no sign of any civilian impact in the strike conducted Saturday night and each participating jet returned to base without incident, the defence officials confirmed.
The British jets were supported by a Voyager refuelling tanker.
IS - referred to as Daesh - enforced militant control over significant areas in Syria and Iraq until 2019.
"This operation demonstrates our UK leadership, and determination to operate in unison with allied nations, to stamp out any revival of Daesh and their harmful and extremist ideologies in the area," UK Defence Secretary the minister remarked.
UK warplanes have conducted surveillance missions over Syria to "forestall any efforts to regroup" of Islamic State following its military defeat at the Baghuz confrontation in 2019, the authorities noted.
"I must thank every member of our armed forces participating in this mission for their professionalism and their courage," the Defence Secretary added. "They were among a great many British personnel deployed over the festive period. This action, to take out militants who pose a risk to our way of life, highlights how British military are prepared to act, continuously, ensuring Britain's security at home and powerful internationally."
In December, the American forces carried out what it termed a "massive strike" targeting IS targets in the country, after an ambush resulted in the deaths of two US troops and a civilian interpreter in Palmyra.
The U.N. reports Islamic State still has between 5,000 and 7,000 militants in Iraq and Syria.
