issue, but it's not that easy," Koizumi told reporters.
The dispute is "not an issue that can be resolved immediately if Japan becomes hasty in trying to settle it," he said.
Koizumi and Putin have already agreed that the Russian leader will visit Japan in the first half of 2005. Putin last visited Japan in 2000.
Japan apparently wants to resolve the territorial dispute on the leverage of Putin's visit.
Foreign Minister Nobutaka Machimura met Friday in Russia with his counterpart, Sergei Lavrov, to lay the groundwork for Putin's visit.
During the foreign ministerial talks, however, the two countries remained far apart over the territorial dispute and failed to detail a plan for the visit.
The dispute involves the islands of Etorofu, Kunashiri and Shikotan, and the Habomai islets, which the Soviet Union seized at the end of World War II.
Japan has demanded the return of all the islands seized by the Soviets, but Russia maintains that only Shikotan and the Habomais are subject to being returned. The dispute is an obstacle to the countries signing a World War II peace treaty.
Lavrov on Friday dismissed Japan's claim of sovereignty over all the islands, Japanese officials said earlier.
Russia has been saying it is prepared to settle the dispute in line with an agreement between Japan and the Soviet Union in 1956.
The agreement said Russia concedes only Shikotan and the Habomais.