RAF Typhoon fighter aircraft were scrambled to monitor two Russian planes approaching UK airspace, the Ministry of Defence has said.
The Russian Blackjacks long-range bombers were not talking to air traffic control, making them a hazard to all other aviation, the department said.
RAF Lossiemouth-based fighter jets intercepted the bombers over the North Sea between 40 and 100 nautical miles from the coast, according to the RAF.
They added the Russian aircraft were in the UK “area of interest”, although they did not enter UK territorial airspace.
Defence Secretary Gavin Williamson said: "Russian bombers probing UK airspace is another reminder of the very serious military challenge that Russia poses us today.
"We will not hesitate to continually defend our skies from acts of aggression. Once again the rapid reactions of our RAF have demonstrated how vital our Armed Forces are in protecting Britain."
Russian aircraft are routinely intercepted, identified and escorted by the RAF.