Russia said on Wednesday it had flown two nuclear-capable TU-160 bombers to a far eastern Russian region opposite Alaska as part of a training exercise that state media said showed Moscow's ability to park nuclear arms on the United States' doorstep.

The Tupolev TU-160 strategic bomber, nicknamed the White Swan in Russia, is a supersonic Soviet-era aircraft capable of carrying up to 12 short-range nuclear missiles and of flying 12,000 km (7,500 miles) non-stop without refueling.

Russia's Ministry of Defense said in a statement that the planes had covered a distance of over 6,000 km (3,728 miles) in over eight hours from their home base in western Russia to deploy in Anadyr in the Chuktoka region which faces Alaska.

It said the flight was part of a tactical exercise that would last until the end of this week and was designed to rehearse the air force's ability to rebase to operational air fields and to practice air-to-air refueling.

Russian government newspaper Rossiiskaya Gazeta said on its website that the flight showed Moscow's ability to base nuclear bombers within 20 minutes flight time from the United States, which it said was just over 600 km (372 miles) away.

TU-160s have flown from bases in Russia to Syria where they have bombed forces opposed to President Bashar al-Assad, one of Moscow's closest Middle East allies.

The defense ministry said a total of around 10 TU-160 bombers and TU-95MS and IL-78 planes were involved in the exercise, suggesting it covered other areas too.