RAF jets have been scrambled for the second time in two days to intercept an approaching aircraft.
Typhoons from RAF Lossiemouth were sent from their base near Moray on Thursday, due to an unknown aircraft approaching the UK area of interest.
The mission is being supported by a Voyager Tanker from RAF Brize Norton.
It comes after fighter jets were launched from the Moray base on Wednesday to escort four Russian bombers away from UK airspace.
The RAF Typhoons escorted the Russian aircraft, which were two Tu-95 Bear H and two Tu-142 Bear F, out of the UK’s area of interest.
The incidents come amid rising tensions between Ukraine and Russia, as the prospect of a Russian incursion looms.
An RAF spokesman said: “Quick reaction alert Typhoon fighters from RAF Lossiemouth, supported by a Voyager Tanker from RAF Brize Norton, have been launched against aircraft approaching the UK area of interest.
“We will not be offering any additional detail on this ongoing operation until complete.”