Britain has scrambled Typhoon fighter jets to see off Russian military planes flying close to its airspace off the coast of Scotland, a spokeswoman from the defence ministry said.
"There were unidentified aircraft flying near the north of Scotland," the spokeswoman told Reuters, saying Britain's Royal Air Force had later identified them as Russian.
"They were flying in international airspace at all times, they didn't go into UK sovereign airspace," she added, saying there had been eight similar incidents in 2013.
Local media reported there were two Russian planes, believed to be Tupolev-95s, which had turned away and flown towards Scandinavia after being contacted by the British jets.
Defence experts says Russia uses such surveillance flights to remind the world of its military might and to probe other countries' air defence systems.