Putin's actions in Crimea have prompted military deployment from Nato
Theresa May has sanctioned the scrambling of British RAF resources to patrol the skies over the Black Sea alongside local jets.
Defence Secretary Sir Michael Fallon said four Typhoons from 3 (Fighter) Squadron will lead the deployment, part of the Nato southern air policing mission.
The Typhoons, from RAF Coningsby in Lincolnshire, will spent up to four months based at Mihail Kogalniceanu airbase in south east Romania.
Defence Secretary Sir Michael Fallon announced the jets would be sent to Romania
The UK is stepping up its support for Nato's collective defence from the north to the south of the alliance
Sir Michael also confirmed UK investment in developing cyber warfare capabilities and skills, including the ability to launch online attacks.
He said: "The UK is stepping up its support for Nato's collective defence from the north to the south of the alliance.
"With this deployment, RAF planes will be ready to secure Nato airspace and provide reassurance to our allies in the Black Sea region."
Sir Michael had already indicated that RAF jets would join the Nato operation in Romania, but he confirmed the date of the deployment and the squadron at an event in London.
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Typhoon jets are being scrambled to Romania
At the international parliamentary conference on national security, Sir Michael said an already-announced £1.9billion investment in cyber security would help develop skills and capabilities across government.
He said: "Our military is among the best prepared in the world to tackle cyber threats with capabilities and skills integrated into the Army, Royal Navy, and the RAF. But in such a dynamic environment we must continually test and enhance our skills.
"We're interested not just in defensive but also in offensive cyber, those who threaten cyber-attacks against us need to know the risk they're running."
Russia sees Romania as "a clear threat" and a Nato outpost due to it hosting elements of a US anti-missile shield.
Vladimir Putin has insisted Nato is showing aggression on Russian borders
The Trump military claims its positioning is to protect from Iran, but Mr Putin’s country is suspicious.
The US has been accused of aggression on Russia’s borders after Nato troops were deployed to Poland and strengtheded in Lithuania.
US and Nato officials say the move is needed to provide extra security and reassurance to European countries after Russia's 2014 annexation of Ukraine's Crimea.