The British military acknowledged for the first time on Tuesday that its fighter jets carried out a joint excercise with their Israeli counterparts. The United Kingdom's Permanent Joint Headquarters posted on Twitter about the F-35 training exercise, which also included American aircraft.

The announcement comes at a time of heightened military cooperation between the United Kingdom and Israel. Israeli aircraft will, for the first time, participate in an exercise in the Combat Warrior exercise in Britain in September.

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Also on Tuesday, Britain's defense secretary said the country's most advanced military aircraft, the Lightning F-35B, has flown its first missions over Syria and Iraq as part of the ongoing operations against the Islamic State group.

A statement released Tuesday quoted Defense Secretary Penny Mordaunt as saying that the jets' first operational mission from a British air base in Cyprus where they have been undergoing training since May 21 is "a significant step into the future for the U.K."

British military officials had said there were no plans for the aircraft to conduct combat missions during their stay at RAF Akrotiri.

But it was decided that they were ready to make their operational debut because of their "exceptional performance."

Officials said the aircraft didn't fire any weapons when flying alongside Typhoon jets.

The Associated Press contributed to this report.