SEOUL, South Korea -- North Korea dealt a blow Tuesday to prospects for further multilateral talks aimed at curbing its nuclear weapons development, saying it will not allow Japan to participate in any new dialogue because it is untrustworthy.

Japan firmly rejected the North Korean position, saying it had a role to play in any talks on the nuclear issue. "We simply cannot accept such a statement," Japanese government spokesman Jiro Okuyama said at a regional summit in Bali.

Although North Korea frequently issues belligerent statements, often as a way to gain leverage over its adversaries, its latest assertion complicates efforts by the United States and its allies to restart six-nation nuclear talks. Washington considers Japan's participation crucial, saying North Korea's nuclear programs threaten regional security.

In New York, the U.S. ambassador to the United Nations, John Negroponte, said Japan's interests must not be excluded.

"We must recognize that the country of Japan has a vital interest in developments on the Korean peninsula," Negroponte said. "Any solution to the problems on the Korean peninsula is going to have to take into account the vital interests of Japan."

In August, the United States, China, Russia, the two Koreas and Japan held talks in Beijing aimed at addressing the North's nuclear ambitions. Tokyo used the talks to raise another issue it considers pivotal -- abductions of its citizens decades ago by the communist state.

On Tuesday, North Korea's Foreign Ministry said it "would not allow Japan to participate in any form of negotiations for the settlement of the nuclear issue in the future."

It was unclear whether the statement, carried by the North's official KCNA news agency, meant North Korea would agree to a future meeting if Japan is excluded. Ever since the August meeting ended without plans for a next round, North Korea has said it is no longer interested in further talks.

"Japan is nothing but an obstacle to the peaceful settlement of the nuclear issue between the DPRK and the U.S.," the North Korean statement said, using the acronym of the North's official name, Democratic People's Republic of Korea. "It has lost its qualification to be a trustworthy dialogue partner."

North Korea accused Japan of abusing the nuclear talks to raise the "issue of abduction," which the North says has already been settled.

The kidnapping of Japanese during the 1970s and 1980s by North Korea to train its spies has been a major sticking point between the Asian neighbors, stalling efforts to set up diplomatic relations and halting Japan's food aid to the impoverished North.

The Japanese public was outraged when North Korean leader Kim Jong Il admitted in September 2002 that his nation's agents had systematically kidnapped Japanese decades ago. North Korea has allowed the return of five kidnapped Japanese.

In Tokyo, the Foreign Ministry said in a statement that if future talks are to occur, "Japan's participation is natural."

"The nuclear, missile and abduction issues must be resolved if Japan-North Korea normalization negotiations are to move forward," it said.

Japan, China and South Korea agreed Tuesday to coordinate efforts to get North Korea to end its nuclear ambitions and reiterated that the dispute should be resolved peacefully.

The agreement between Japanese Prime Minister Junichiro Koizumi, South Korean President Roh Moo-hyun and Chinese Premier Wen Jiabao came on the sidelines of the annual summit of the 10-nation Association of Southeast Asian Nations, held on the Indonesian resort island of Bali.

A South Korean government official, who spoke on condition of anonymity, said the three leaders agreed to cooperate in setting up a second round of six-party talks but that no date has been set.

The United States keeps 37,000 American troops in South Korea -- a legacy of the 1950-53 Korean War.