Britain scrambled two Royal Air Force Typhoon jets from Scotland to intercept Russian planes close to the United Kingdom's airspace, a defence ministry spokesman said.
The Typhoons took off from RAF Lossiemouth in Moray, Scotland, at around 9:30 am to tackle the alleged encroachment. A RAF spokesman said: "This is a live operation and therefore we will not be providing any additional information until the mission is complete.”
The Russian plane model is yet to be identified as the operation is still ongoing. French and Belgian air forces have reportedly also been deployed to tackle the situation.
Air traffic monitors appear to show the RAF jets being trailed by the British Voyager aircraft from RAF Brize Norton, Oxfordshire, which can provide air-to-air refueling capabilities to the Typhoons. The aircraft were spotted near Caithness on the east coast of Scotland on Monday morning.
It follows a string of incidents between the RAF and Russian air forces over the past months. In September, two RAF Typhoons were scrambled to monitor a pair of Russian planes reportedly flying into UK airspace.
RAF Typhoon jets have been used since 2007 in offensives against the Islamic State (ISIS/ ISIL), with pilots carrying out missions lasting up to eight-hours.
The 1,500 mph armed fighter jets incorporate air-to-air missiles and are an integral part of the RAF's Quick Reaction Alert.