UK jets intercepted 3 Russian military aircraft en route to the Baltics
The British fighters, scrambled from the Amari air base in Estonia, intercepted the Russian aircraft, which were not transmitting a recognized identification code and were unresponsive, the ministry said.
"We were able to instantly respond to this act of Russian aggression - demonstration of our commitment to NATO's collective defense," Defence Secretary Michael Fallon said in a statement.
The latest Russian interception comes one month after two Russian warplanes with no visible weaponry flew simulated attack passes near a US guided missile destroyer in the Baltic Sea.
The repeated flights by the Sukhoi SU-24 warplanes, which also flew near the ship a day earlier, were so close they created wake in the water, with 11 passes, the official said.
The incident came as NATO plans its biggest build-up in eastern Europe since the Cold War to counter what the alliance, and in particular the Baltic states and Poland, consider to be a more aggressive Russia.
The three Baltic states, which joined both NATO and the European Union in 2004, have asked NATO for a permanent presence of battalion-sized deployments of allied troops in each of their territories. A NATO battalion typically consists of 300 to 800 troops.
(Reuters reporting by Guy Faulconbridge)