RAF jets have intercepted four Russian jets following a 'Quick Reaction Alert' mission on Wednesday.
Typhoon fighters from RAF Lossiemouth, supported by a Voyager Tanker from RAF Brize Norton, launched northwards against what was originally "unidentified aircraft" approaching UK airspace.
The four Russian Bear aircraft were then intercepted and escorted out, according to the Royal Air Force.
According to the RAF, the Russian jets did not enter UK airspace.
They were a Tu-95, which is a large, four-engine turboprop-powered strategic bomber and missile platform.
A Ministry of Defence spokesperson told the Mirror that "Quick Reaction Alert Typhoon fighters from RAF Lossiemouth" had been launched.
"We will not be offering any additional detail on this ongoing operation until complete," they added.
UK Defence Journal editor, George Allison, said earlier today on Twitter the Voyager tanker is squawking, or transmitting transponder code 1321, meaning it is conducting a NATO air policing mission - "which aims to preserve the security of Alliance airspace".
He added an open source intelligence specialist has confirmed that at least three Russian bombers are in the air with the support of three tankers and an A-50 AWACS aircraft.
While Russian strategic bomber communications are said to have been active today.
Two F-15s and two tankers were reported to be flying over East Yorkshire around midday.
A NATO E-3 AWACS - an American airborne early warning and control aircraft aircraft - is also said to be heading north.
Portuguese F-16s were also seen launching from Lossiemouth but it is understood they are not involved and are headed for Iceland.
In an article in UKDJ about the incident, Mr Allison explained the difference between the UK area of interest and UK sovereign airspace.
He said: "Sovereign airspace is that airspace above the territory of a nation and the area of interest includes international airspace for which a country is responsible in some way, such as the provision of air traffic control services.
"Entering an area of interest is fine, routine and something normal. Entering national sovereign airspace is not. These aircraft are not likely to enter British sovereign airspace."
It comes hours after a Russian warplane "breached the air space of Estonia" where hundreds of British troops are based.
In a move seemingly designed to test NATO defences, the alleged aerial incursion saw a Su-27 fighter soar the Gulf of Finland.
The warplane did not post a flight plan and its transponder was switched off as it violated the Estonian frontier, officials in Tallinn claimed.
They described the incursion as “a very unfortunate and serious incident”.
“The jet remained in Estonian airspace for less than a minute," a spokesperson for the NATO member state said.
"It was flying with the transponder in the off mode and remained out of contact with Estonian air traffic control at the time of violating the Estonian state border."
In November last year British Typhoon jets intercepted two Tu-160 Russian bombers.
Nicknamed the White Swan, the supersonic jet is nuclear capable and often sent on probing missions to test NATO.
The long-range strategic bombers were escorted away and did not enter UK airspace.
The Russian Ministry of Defence said at the time that its aircraft, of the same type as were intercepted, had conducted a patrol over Belarusian airspace.
The latest intervention action comes as Russia continues to amass tens of thousands of troops and tanks close to the Ukrainian border amid fears of an invasion.
