Japanese officials say they have high expectations for improved bilateral relations going into Friday's summit between Prime Minister Shinzo Abe and his Russian counterpart Vladimir Putin, in which a long-standing territorial dispute and a potential visit to Tokyo by the Russian leader will likely be discussed.

The scheduled unofficial three-and-a-half hour meeting in the southern Russian city of Sochi comes at the end of Abe's weeklong visit to Europe. He made stops in Italy, France, Belgium, Germany and Britain to lay the groundwork for the Group of Seven summit Japan is hosting later this month.

The unofficial nature of the stop, where there will be no official ceremonies or a joint news conference, is intentional, according to a high-ranking foreign ministry official, so Abe and Putin can hold frank, one-on-one talks.