Tokyo's policy in recent years has destroyed the positive groundwork in Russian-Japanese relations, reducing bilateral ties to an "ice age," Russian Ambassador to Japan Nikolai Nozdrev said on Monday.

"We are witnessing a decline unprecedented in the entire post-war era, if I may call it that, a deep 'ice age' in bilateral relations," he said in an interview with Russia's RIA Novosti news agency.

The positive groundwork accumulated over the past decades "has been almost completely destroyed" by Tokyo in joining "the anti-Russian line of the collective West in the context of the Ukrainian crisis," he said.

The ambassador has laid out the essential prerequisites for restoring state-to-state contacts. He called on Tokyo to abandon its current hostile stance, cease its revisionist policies and reverse its course toward remilitarization.