Russia's defence ministry said on Tuesday that two of its Tu-95MS strategic bombers had conducted a flight of more than 12 hours over the Pacific Ocean, the Bering Sea and the Sea of Okhotsk.
The flight by the nuclear-capable planes came at a moment of high tension in Russia's war with Ukraine and its confrontation with the West, after NATO and the United States said they expected Russia to test its nuclear forces imminently.
The aircraft were escorted by MiG-31 fighter planes, and refuelled while in the air, the ministry said. It described the mission as "a scheduled flight over neutral waters", in line with international airspace rules.
The ministry did not specify the route, but a flight path over the Sea of Okhotsk and the Bering Sea would have passed close to Japan and the United States.
NATO is conducting nuclear preparedness exercises this week and has said it expects Russia to hold its own nuclear drills imminently. The Kremlin said earlier on Tuesday it had no information on that.
U.S. officials have said they expect the Russian exercises to include the test launch of ballistic missiles.
President Vladimir Putin warned on Sept. 21 that he was prepared to defend Russia's "territorial integrity" by all means, including nuclear weapons if necessary.
The next week, he proclaimed Russia was absorbing four Ukrainian regions - an action overwhelmingly condemned as illegal by the United Nations General Assembly - and taking them under its nuclear umbrella.
Western officials are concerned about the timing of the Russian exercises but have expressed confidence in their ability to discern the difference between a Russian drill and any move by Putin to make good on his threats.
(Reporting by Reuters; writing by Mark Trevelyan, Editing by Kevin Liffey)