WASHINGTON — Relations may be thawing between the Cold War enemies on the divided Korean peninsula, but that doesn't mean U.S. troops there will be withdrawn any time soon, says South Korean Ambassador Lee Hong-koo.

A top priority of Communist North Korea for years has been to seek withdrawal of 37,000 American soldiers posted across the demilitarized zone in defense of rival South Korea.

But Lee says North Korea knew not to bother to bring it up this week, when the two nations held a historic presidential summit to work for improved relations.

Asked in an interview whether the summit will lead to a U.S. troop withdrawal, Lee said: "That's a long way off."

A former South Korean prime minister and unification minister, Lee said the North Koreans were told many times before the summit that if they bring up the troop issue first, "it won't go anywhere."

For the time being, he said, "we are not prepared to discuss this issue. The North Koreans understood this. So we don't expect any problem."

Lee spoke hours after North Korean leader Kim Jong Il and South Korean President Kim Dae-Jung signed an agreement in Pyongyang pledging to work for reconciliation and eventual reunification.

"China heartily rejoices at the success of the summit and wishes to express its congratulations," Foreign Ministry spokesman Zhu Bangzao told reporters in Beijing.

"We hope the two sides will continually enhance mutual respect in a spirit of compromise and cooperation and strengthen exchanges and cooperation in every field in order to create favorable conditions to realize final, peaceful reunification of the Korean peninsula," Zhu said.

Meanwhile, Gen. Henry H. Shelton, chairman of the Joint Chiefs of Staff, said "it's probably premature to leap to any conclusions" about cutting U.S. troop levels on the Korean peninsula.

Shelton commented in response to a reporter's question after a Korean War 50th anniversary ceremony at Arlington National Cemetery. He did not rule out future troop reductions in Korea.

"I think that at this point we should wait and see what actually comes officially out of the talks today," he said. "There's been no mention to my knowledge made on either side of any troop reductions."

The United States announced in September that it was easing sanctions against North Korea that have been in place for 50 years.

The summit is unlikely to affect U.S. plans for a missile defense system, according to the State Department. North Korea's missile program has been cited as a major justification for deployment.

"I don't think we see in (the summit) the seeds of anything that would change the possibility of a missile threat to the United States that we would have to deal with," said spokesman Richard Boucher.

Beijing also fears a theater missile defense plan being developed with Japan is aimed at blocking its rise as an Asian power and protecting Taiwan.