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North Korea should not resume missile tests in keeping with a previous international agreement, an official traveling with Japan's prime minister said Sunday.

On Saturday, North Korea's ambassador to China, Choe Jin Su, said his country might end its moratorium on ballistic missile tests if the United States does not take steps to improve relations.

Pyongyang agreed with the United States in October 2000 not to test long-range missiles. In a summit with Prime Minister Junichiro Koizumi last September, North Korean leader Kim Jong Il vowed to continue the moratorium through this year.

"We believe this moratorium on the firing of the missiles and their (North Korea's) commitment should continue to be observed," the Japanese official said on condition he not be further identified.

North Korea alarmed the world and heightened regional tensions when it test-fired a missile in 1998 that flew over Japan and landed in the Pacific Ocean.

Koizumi wrapped up his four-day visit to Russia with a stopover Sunday in this frontier city in Russia's Far East to stress Japan's interest in Russia's energy resources. But concerns over North Korea followed him to Khabarovsk.

Koizumi met with Konstantin Pulikovsky, Putin's representative in the Russian Far East who has close ties to North Korea's leader.

Pulikovsky and Koizumi discussed North Korea's nuclear development program and a deadlock between Tokyo and Pyongyang over the fate of several Japanese abducted by North Korean agents decades ago.

The five known surviving abductees are now in Japan, but North Korea has demanded they be returned. The tug-of-war has chilled a budding detente between the two Asian neighbors.

Japanese officials said Pulikovsky described North Korea's Kim as a man who could be reasoned with, but who must be treated fairly.

"He reacts when he feels he is being pressured from outside," Pulikovsky said, according to a Japanese delegation official. "But he can be negotiated with if he is treated as an equal partner."

Koizumi has denied rumors he wants to enlist Pulikovsky to act as a go-between with Kim.

In Moscow, Koizumi and Putin signed a pact outlining the need to expand ties and settle a territorial dispute that has kept the two countries from concluding a peace treaty after World War II.

Koizumi also urged Putin to push forward with projects to tap Siberia's energy resources and build a pipeline from Siberia to the Pacific. Access to Russian oil and gas is important to resource-poor Japan, which relies heavily on oil from the Middle East.

Japanese officials said Putin expressed concern over the financing of the projects and possible environmental problems the development might cause.