A tug of war between Russian government officials has led Moscow to seek a monthlong postponement of the planned summit in Siberia between Japanese Prime Minister Yoshiro Mori and Russian President Vladimir Putin, a senior Foreign Ministry official said Tuesday.

"There is heightened tension within the Russian government" over the territorial dispute with Japan, Kazuhiko Togo, director general of the ministry's European Affairs Bureau, told the ruling Liberal Democratic Party's joint division on foreign affairs.

"In Russia, there are those who want to delay negotiations over the territorial dispute as much as possible and those who want to have good relations with Japan, and they are engaged in a tug of war," Togo said.

This tension, he said, has prompted Russia to request that the next Mori-Putin meeting be scheduled for late March despite the tentative agreement between Japanese Foreign Minister Yohei Kono and Russian Foreign Minister Igor Ivanov to slate the Irkutsk summit for Feb. 25 to 26.

The territorial row -- involving Japan's claims to the islands of Etorofu, Kunashiri, Shikotan and the Habomai group of islets, which were seized by Soviet troops at the end of World War II -- has prevented Japan and Russia from concluding a bilateral peace treaty.

Russian officials who want to delay resolving the dispute were threatened by remarks Putin made during his visit to Tokyo last September, when he said the 1956 Japan-Soviet joint declaration, stating Moscow will return Shikotan and Habomai to Japan after concluding a peace treaty, is valid, Togo said.