TOKYO - North Korea warned yesterday that unless relations with Japan were quickly normalized it would resume its testing of ballistic missiles.

The thinly veiled threat was issued by an unidentified Foreign Ministry spokesman less than a week after the first high-level talks between the two countries in two years, in Kuala Lumpur, Malaysia, ended in an angry stalemate.

Tuesday's statement said that the "relevant organs" would "reconsider the moratorium on the missile test-fire in case the talks on normalizing the relations between North Korea and Japan get prolonged without making any progress, as was the case with the recent talks."

North Korea shocked Japan in 1998 with a surprise test of a Taepodong intercontinental ballistic missile, which overflew Japan. North Korea later claimed that the missile test was a satellite launch, and has refrained from further testing for several years. It reaffirmed a self-imposed moratorium on missile testing six weeks ago in a meeting between North Korea's leader, Kim Jong Il, and Prime Minister Junichiro Koizumi of Japan.

Speaking yesterday in Phnom Penh, Cambodia, where he was attending a meeting of the Association of Southeast Asian Nations, Koizumi dismissed the warning, saying it did not figure in any government-to-government communication.

He expressed confidence that Japan's diplomatic engagement with the North would bear fruit. "I believe North Korea will not do anything to trample the spirit of the Pyongyang declaration," Koizumi said.

During Koizumi's one-day meeting with Kim, the North Korean leader pledged not only to continue to observe its missile test moratorium, but also to abide by international obligations regarding nuclear weapons. The meeting seemed to put the two countries on a fast track toward establishing diplomatic relations.

Since the demise of the Soviet bloc, North Korea has suffered famines and severe economic hardships. In preparatory negotiations, Japan offered large financial incentives to the North to change its repressive, militaristic behavior, promising a major aid package in case of normalized relations.

Since the Sept. 17 meeting, the United States announced that North Korea had acknowledged the existence of a secret uranium-based nuclear weapons development program.

Until now the principal issue separating Japan and North Korea had been North Korea's kidnapping of 13 Japanese citizens for use as trainers in the country's spy program. Washington's insistence that North Korea eliminate its secret weapons program before receiving Japanese economic aid has revived tensions.