Japan's top security official has left for Moscow to discuss the situation in Ukraine and lay the groundwork for a visit by Russia's President Vladimir Putin to Japan.

Shotaro Yachi, the head of the National Security Secretariat, left Japan on Monday for a three-day visit to Russia and Britain, according to Japan's (NHK WORLD) website.

Yachi will meet with Russian Security Council Secretary Nikolai Patrushev, a close aide to Putin, in Moscow, and the British National Security Adviser, Kim Darroch, in London.

In Moscow, Yachi will discuss ways to promote dialogue between Japan and Russia. Japan's Prime Minister Shinzo Abe wants Putin to visit Japan this year. They are also expected to exchange views about the Ukrainian crisis.

In London, Yachi and Darroch are expected to discuss the outcome of Sunday's referendum in Greece after voters rejected austerity measures.