Citing the Russian Defense Ministry, TASS said Russian air defense detected an aircraft on Tuesday at around 10 a.m. local time (0700GMT) over the Baltic Sea.
Russia claims it intercepted a US B-52 bomber that was flying near the border of Russian airspace.
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Russia has based nuclear-capable Iskander missiles at its Kaliningrad exclave in the Baltic, and North Atlantic Treaty Organisation says Russian air patrols have increased in the region.
North Atlantic Treaty Organisation members such as Britain regularly report scrambling jets to intercept Russian nuclear-capable bombers flying close to their air space.
The incident is the latest is a series of wargames and mid-air interceptions that highlight the inherently risky cat-and-mouse game played by the major superpowers on contested airspace. It is less common for Russian Federation to report using its fighters for the same reason.
It comes as more than 4,000 allied North Atlantic Treaty Organisation troops take part in the drills in the Baltic Sea, the Arctic and along Russia's border. Russia's Defence Ministry identified the plane as a P-3 Orion anti-submarine aircraft.
A spokesperson for the US Naval Forces said the two planes came within 20 feet of each other in an "extremely close encounter". Moscow was more put out by the B-52's appearance.
Several B-52s, along with a contingent of maintenance troops arrived in the United Kingdom in recent days to participate in North Atlantic Treaty Organisation exercises happening this summer.
The bomber, normally based in Barksdale, Louisiana, is now stationed at RAF Fairford in Britain in support of North Atlantic Treaty Organisation exercises. Sabre Strike, one of the multinational exercises, began last month and will take place in Poland, Latvia and Lithuania in coming weeks. In another dramatic incident past year, Russian jets buzzed over the USS Donald Cook in the Baltic Sea, coming within 30 feet of the American warship.
The B-52 was created to attack Moscow's most vital targets via the North Pole in the event of a nuclear war when the Soviet Union still existed, Mr Deinekin said.
It flew close to the danger zone.