A senior Russian official said Thursday that a solution to the decades-long territory dispute with Japan concerning the Kuril Islands may take a long time and require a lot of negotiations.

Deputy Foreign Minister Alexander Alexeyev reiterated Russia's position on the issue, saying Moscow was not prepared to return all the four islands back to Japan, where the islands are called the Northern Territories.

His comment came on the same day when Japanese Foreign MinisterNobutaka Machimura arrived here for talks to be held on Friday forimproving bilateral relations that have been troubled for decades by the dispute.

Japan has been demanding the return of the four islands, captured by Soviet Red Army troops at the end of World War II in the 1940s, but the Russians only agreed to hand back two of them.

Alexeyev said that there was a fundamental disagreement betweenMoscow and Tokyo on the issue and "it will require a lot of detailed negotiation", reported Russia's Interfax news agency.

He also said that no specific date has been set for a planned visit to Tokyo by Russian President Vladimir Putin.

Earlier reports said that Putin's visit to Japan, probably in this month or February, would coincide with the commemoration of the signing of the first treaty between Japan and Russia 150 yearsago.

But Alexeyev's comments on Thursday may mean that the visit might have been put on hold or could be canceled if no progress ismade on the controversial islands dispute.

Source: Xinhua