RAF jets were scrambled on Wednesday after two Russian military aircraft were seen off the Cornwall coast, the Ministry of Defence says.
An MoD spokesman said the two planes were escorted by the RAF until they were out of the “UK area of interest”.
The Russian Bear bombers did not enter UK sovereign airspace, he added.
Defence Secretary Michael Fallon has warned there is a “real and present danger” of Russia trying to destabilise three Baltic states.
On Wednesday, Mr Fallon spoke of his concerns about Russian interference in Latvia, Lithuania and Estonia.
Part of a trend
The MoD said: “RAF Quick Reaction Alert Typhoon fighter aircraft were launched [on Wednesday] after Russian aircraft were identified flying close to UK airspace.
“The Russian planes were escorted by the RAF until they were out of the UK area of interest. At no time did the Russian military aircraft cross into UK sovereign airspace.”
The BBC’s political correspondent Ross Hawkins says that, according to the Department for Transport, there was no record of disruption to civil aviation as a result of the bombers’ presence.
He said the incident was part of a trend of Russian aircraft flying close to UK airspace and there have also been concerns about similar incidents across Europe.
It is a show of strength from the Russians, and such incidents are carried out with political intent as the Russian government knows it will be noted and reported on, our correspondent added.
A similar incident occurred in January, when the UK Foreign Office said two Russian Tu-95 Bear H bombers flying near UK airspace had caused “disruption to civil aviation”.
They were also escorted by RAF jets throughout the time they were in the “UK area of interest”, according to officials.