The Royal Air Force has launched Typhoon jets after undisclosed aircraft approached what an RAF spokesman described as the UK’s “area of interest”, a day after jets responded to four Russian strategic bombers approaching the same area.

The spokesman confirmed the Typhoons, launched from RAF Lossiemouth in Moray, northern Scotland, have been joined by a Voyager air-to-air refuelling tanker from RAF Brize Norton in Oxfordshire.

He said further information will not be disclosed “on this ongoing operation until complete”.

The news comes after RAF jets responded to four Russian strategic bombers approaching the UK’s “area of interest” on Wednesday.

The bombers were “intercepted and escorted”, a spokesman said, and at no point did they enter UK airspace.

Footage released by the Russian Ministry of Defence earlier on Thursday showed a Russian bomber, of the same type that was intercepted on Wednesday, being flanked by two RAF jets while on “a planned flight”