Prime Minister Junichiro Koizumi should offer concessions in the territorial dispute with Russia to pave the way for a post-World War II peace treaty, according to a Russian expert on Japan.

"The only way to resolve bilateral issues is for Mr. Koizumi to compromise with Russia," Victor Pavlyatenko, chairman of the Center for Japan Studies at the Institute of Far Eastern Studies, said in a recent interview.

Former Prime Ministers Ryutaro Hashimoto and Yoshiro Mori "had the courage to compromise, but Prime Minister Koizumi lacks it," he said. Koizumi "does not have his own vision in diplomacy toward Russia and he has shown a tendency during the past two years of putting the bilateral disputes on the back burner."

Koizumi is scheduled to depart Thursday for a trip to Russia.

Pavlyatenko, 55, said that while Japan expects to regain control of the four disputed islands off Hokkaido, "Russia cannot accept such a stance."

Soviet troops seized the islands from Japan at the end of the war. Resolving the dispute is a condition for signing a peace treaty, a loose end from the war that Japan and Russia have been unable to mend.

"Japan should know it is likely that Moscow will refuse to continue negotiations over the territorial issue if it sticks to its policy," he said.

On Japan's expectations that Russia will persuade North Korea to cooperate with the international community, Pavlyatenko said it is necessary for Tokyo to act independently of U.S. policies if it expects Moscow to play a key role in North Korean issues.

It will be difficult for Japan and Russia to cooperate in addressing North Korean issues unless they make some concessions in their own bilateral problems, he added.