RAF Typhoons were scrambled three times in 24 hours to intercept Russian jets attempting to fly close to NATO exercises being conducted in the Baltic.
The British aircraft are currently based in Estonia, where 17 countries are taking part in BALTOPS 2015.
The exercises which involved 49 ships, 61 aircraft, 1 submarine and 5,600 troops, are taking place across Poland, Sweden, Germany and throughout the Baltic Sea, and are intended to demonstrate solidarity with Eastern Europe in the face of a potential Russian threat.
The Royal Navy Flagship HMS Ocean is taking part in an amphibious landing exercise on a beach in northern Poland, less than 100 miles from the Russian state of Kaliningrad.
The deployment of the aircraft came as Britain warned Moscow the NATO exercises were "not a game". Defence Secretary Michael Fallon added that the UK will "stand tall, shoulder-to-shoulder" with other alliance members to defend eastern Europe's borders.
Moscow has however, responded to the warnings, accusing NATO of re-igniting memories of the Cold War by encroaching on its borders, as East-West tensions remain high over the continuing crisis in Ukraine.
Kremlin spokesman Dmitry Peskov said: "It's not Russia that's approaching someone's borders. It's NATO's military infrastructure that is approaching the borders of Russia. All this ... forces Russia to take measures to safeguard its own interests, its own security."
Russian President Vladimir Putin has warned that Moscow would increase its stockpile of nuclear missiles in response to plans by Washington to base heavy military hardware in eastern Europe.
NATO Secretary General Jens Stoltenberg in turn accused Putin of "sabre rattling."
There has been a marked increase in Russian air activity in the last six weeks with RAF intercepts of Bear bombers and reconnaissance aircraft now in double figures.
Earlier this year, Russian warships passed through the English channel as they sailed to observe NATO's Exercise Joint Warrior which took place off the coast of Scotland.
In February, Air Chief Marshal Sir Michael Graydon, the former head of the RAF said that "Britain is at the mercy of Russian aircraft" because of a halving in air defence systems since the end of the Cold War.