Britain has scrambled Typhoon fighter jets to intercept two Russian long-range bombers near UK airspace, the Ministry of Defence said on Tuesday.
Intercepts of Russian aircraft by NATO have increased over the last year amid heightened tensions between the West and Moscow over the Ukraine crisis.
Tuesday's incident came as Britain hosted war games off the coast of Scotland involving more than 50 warships and submarines and 13,000 personnel from 14 countries.
"The Russian aircraft are being escorted by the RAF (Royal Air Force) in the UK area of interest," a Ministry of Defence spokeswoman said.
In January, Britain summoned the Russian ambassador to explain a similar episode, when Russian bombers flew over the English Channel, forcing British authorities to reroute civil aircraft.
The MoD did not give the location of Tuesday's interception