MOSCOW - THE latest Russian nuclear submarine returned to a navy shipyard in the country's north on Friday after a series of tests at sea that an official labelled successful, RIA Novosti news agency reported.

'The sailors executed their mission excellently,' Nikolai Kalistratov, director general of the Sevmash shipyards, said of the tests of the Yury Dolgoruky sub.

The sub is expected to be armed with Bulava ballistic missiles, which are currently being tested, the agency reported.

Russian President Dmitry Medvedev visited the Sevmash shipyards in Severodvinsk earlier this month. -- AFP