Vladimir Putin's airforce has tried to intercept two US nuclear bombers as they carried out exercises over the border of Finland and Russia.

The US planes later landed in Romania at an airbase close to the border with Ukraine, as tensions between the US and Russia continue to soar to worrying levels.

US European Command said a pair of American B-52H Stratofortress strategic bombers flew out of Barksdale Air Force Base, Louisiana on Monday.

The planes belong to the US Air Force's 2nd Bomb Wing, which is assigned to the Global Strike command.

As they flew over the Barents Sea, a Russian MiG-29 and MiG-31 tried to intercept the bombers at around 8am CET on Sunday in a tense confrontation.

The US bombers maintained their course and continued their flight, eventually touching down at the Mihail Kogalniceanu air base in Romania.

While in Romania, the B-52s will carry out exercises and drills with other NATO allies as part of a renewed drive to beef up security, the US military said.

This is the first time that US strategic bombers will operate from Romanian territory.

General James Hecker said: "In today’s global environment, it is vital that we be postured to deliver a range of sustainable capability from great distances.

"This iteration of Bomber Task Force offers an excellent opportunity to refine our agile combat employment tactics, techniques, and procedures.

"Through collaborative efforts with our Allies, the US enables our forces to combat current and future threats."

The B-52H Stratofortress is a long-range, heavy bomber that can perform a variety of missions, capable of flying at high subsonic speeds at altitudes of up to 50,000 feet (15,166.6 meters).

It can carry nuclear or precision guided conventional ordnance with worldwide precision navigation capability.

B-52s played an active role in recent US military operations around the world. During Desert Storm, the bombers delivered 40 percent of all the weapons dropped by coalition forces.