NEW YORK - The United States and North Korea began landmark talks on establishing diplomatic relations, but a State Department official cautioned against high expectations during this week's meetings.

North Korean Vice Foreign Minister Kim Kye Gwan and U.S. Assistant Secretary of State Christopher Hill met for four hours Monday for talks and dinner at the Waldorf Astoria Hotel in New York. They left without making any comments to reporters.

Kim and Hill are to meet again Tuesday amid rising expectations of improved U.S. relations with a country President Bush called part of an "axis of evil" five years ago, along with Iran and prewar Iraq.

This is the first U.S. visit by Kim, North Korea's top nuclear negotiator, since the international standoff over the North's nuclear ambitions flared in late 2002.

Under an agreement reached at six-nation talks in Beijing last month on the North's nuclear program, the U.S. and North Korea are supposed to open bilateral talks on establishing diplomatic ties.

The North, which tested a nuclear weapon last October, agreed to shut down its main nuclear reactor by mid-April as a step toward abandoning its nuclear program in exchange for aid.

State Department spokesman Sean McCormack described this week's meetings as organizational, focused on setting up an agenda.

"I think that he (Hill) will talk to them about how the process might proceed regarding normalization," McCormack said, including taking North Korea off the U.S. list of state sponsors of terrorism and opening the way for a normal trading relationship with the U.S. for the first time.

Last month's deal has touched off strong criticism in Washington, especially among conservatives, who see it as rewarding North Korea for years of bad behavior.

Japan and South Korea, meanwhile, also took steps to improve relations with North Korea.

A senior aide to South Korea's president will visit North Korea this week, an official said Tuesday. South Korea's Yonhap news agency speculated that the purpose of the trip was to set up a summit with North Korean leader Kim Jong Il but South Korean officials denied that a summit was in the works.

In Vietnam, meanwhile, envoys from Japan and North Korea met Tuesday ahead of two-day talks aimed at establishing relations and fulfilling pledges made in Beijing.

Japan's chief envoy Koichi Haraguchi said Japan wants to spend ample time discussing North Korea's history of abducting of Japanese citizens. North Korea wants Japan to atone for the 1910-1945 colonization of the Korean Peninsula and wartime atrocities, including sex slavery of tens of thousands of Korean women.

Japan and North Korea have never had formal diplomatic ties.

Kim's first stop Monday was the Korea Society, a nonprofit organization that promotes greater understanding and cooperation between Americans and Koreans. He spent 4 1/2 hours with an array of academics and VIPs, including former secretaries of state Henry Kissinger and Madeleine Albright.

"We had a very good and fruitful and friendly meeting," Albright told reporters.

A statement issued afterward said participants at the meeting, sponsored by the Korea Society and the National Committee on American Foreign Policy, discussed a range of U.S.-North Korean issues including normalization of relations "in a friendly and forthcoming atmosphere."

Kim arrived in New York late Friday and met over the weekend with South Korea's chief nuclear negotiator Chun Yung-woo.

The first phase of North Korea's disarmament process under the Feb. 13 accord calls on North Korea to shut down its main nuclear reactor and allow UN inspectors back into the country within 60 days.

In return, it would receive aid equal to 50,000 tons of heavy fuel oil from the other countries participating in the nuclear talks -- the United States, South Korea, Russia, China and Japan.

McCormack stressed that the process of normalization must proceed "step by step."

"It is going to have to be a process by which good faith actions are met in turn by good faith actions," he said. "We, of course, intend to abide by our commitments under the agreement. We'll see how the North Korean side lives up to its responsibilities."

The United States has had no diplomatic relations with North Korea since the country was created after World War II, when Korea was split into a communist-dominated North and a U.S.-backed capitalist South.