Royal Air Force Typhoon jets have operated alongside French aircraft in a joint strike on an subterranean weapons facility in Syrian territory used by the IS group, according to the UK's MoD.
The location, located using surveillance, was assessed as housing weapons and explosive materials, the release indicated, and was located in mountains just above Palmyra in Syria's central region.
"The RAF jets utilized laser-guided Paveway IV weapons to strike a series of entry passages leading to the depot... initial indications suggest the strike was effective," the ministry announced.
There was no indication of any civilian casualties in the strike on Saturday evening and all the aircraft made a safe return, the ministry further stated.
The British jets were assisted by a Voyager refuelling tanker.
The Islamic State group - also known as ISIS - established jihadist rule over parts of both Syria and Iraq prior to its 2019 collapse.
"This strike underscores British leadership, and determination to operate in unison with allied nations, to eradicate any resurgence of Daesh and their dangerous and violent ideologies in the area," the British Defence Secretary the minister said.
UK warplanes have performed surveillance missions over Syria to "forestall any attempted comeback" of IS following its military defeat at the Baghuz confrontation in 2019, the MoD reported.
"I want to thank every member of the UK armed forces who took part in this strike for their skill and their courage," he said. "They were among numerous UK service members deployed over Christmas and New Year. This mission, to remove dangerous terrorists who endanger our way of life, demonstrates how UK forces are always on standby, all year round, ensuring Britain's security at home and powerful internationally."
Last December, the American forces executed what it called a "major assault" against Islamic State objectives in the country, after an assault killed two US troops and a civilian interpreter in the Palmyra area.
The UN reports IS still boasts roughly 5-7 thousand combatants in both countries.
