Japan's prime minister also has a high-level meeting coming up. Shinzo Abe is to hold talks with Russian President Vladimir Putin on the sidelines of the Eastern Economic Forum in Vladivostok, which kicks off Friday.

Reports say Abe hopes the discussion will advance talks with the Kremlin on a territorial dispute involving four Pacific islands. But sceptics question whether the approach will generate a breakthrough in a decades-old territorial dispute. Kistanov Valierii, director of a Russia-based Japanese studies center, says any breakthrough in the near future is unlikely.

"There are big differences on basic positions between Russia and Japan. Japan thinks Russia should return all four Pacific islands, but Russia believes Japan should accept the outcome of World War Two and then they can discuss the disputed islands. But Japan won't accept Russia's position. So I think it is hard to see any breakthrough on this territorial dispute coming out of this meeting. Such a forum can't solve a problem like this," Kistanov Valerii, director of Japanese Studies Center, Far Eastern Studies Institute, said.