Shoigu was accompanied by Alexey Likhachev, head of the state nuclear company Rosatom, and visited Novaya Zemlya, in Russia's extreme north, a statement said.

They also inspected a testing site for nuclear weapons used during the Soviet era, where "advanced tests for military weapons and equipment" were taking place, the defence ministry said, without giving details.

Ukraine launched a highly anticipated push in June after stockpiling Western weapons but has struggled to make headway in the face of stiff Russian resistance.

Russia had beefed up its military presence in the Arctic before it launched what Moscow terms a special military operation in Ukraine in February last year.

It has rehabilitated Soviet-era bases and deployed weapons and anti-aerial S-400 systems in the region, which has vast reserves of hydrocarbons and can serve as a major maritime route between Europe and Asia due to global warming and melting glaciers.

Russia views the entry of two countries in the region -- Finland and Sweden -- in the western military alliance NATO as a threat to its security.

Finland joined the alliance in April and Sweden is expected to be formally admitted in the coming months.