Britain's Royal Air Force has scrambled two fighter jets to intercept Russian bombers near UK airspace, in another illustration of ongoing tensions.

The RAF confirmed a "quick reaction alert," deploying Typhoon aircraft from the Lossiemouth base in Scotland as two Tupolev TU-160 Blackjack bombers approached Britain.

"The Russian aircraft were initially monitored by a variety of friendly nation fighters and subsequently intercepted by the RAF in the North Sea," the air force said.

"At no point did the Russian aircraft enter sovereign UK airspace."

Two Belgian F-16 jets from a base at Florennes were also sent to intercept the Russian planes, according to Belgian media.

The incident is one of several in recent years as Russian military planes test NATO and British air defences.

Russia's military has also sought to probe the resolve of naval forces, with warships being diverted to monitor passing naval vessels.

Last week, the HMS Westminster, a Portsmouth-based Type 23 frigate, was ordered to intercept two warships and two supporting vessels passing near UK waters.