The United States (search) and Japan (search) on Saturday strongly urged North Korea to resume international talks about its nuclear weapons program and expressed hope of working with China to ensure peace with Taiwan.

"We share a concern about events on the Korean Peninsula," Secretary of State Condoleezza Rice said at a news conference at the State Department (search) following talks with Defense Secretary Donald H. Rumsfeld and their Japanese counterparts.

"The ministers and I urge North Korea to return to the six-party talks as the best way to end nuclear programs and the only way for North Korea to achieve better relations," Rice said.

But North Korea is not ready to resume those talks and does not want direct meetings with Washington, according to a report earlier Saturday from China's official news agency, which cited an unidentified North Korean foreign ministry spokesman.

"I don't think we offered one-on-one talks with the North Koreans," Rice said in response to a question. "What is there is the six-party talks," she said, adding the "North Koreans do have a path to a better relationship with the international community."

Japan's foreign minister, Nobutaka Machimura, joined Rice in calling for an "early and unconditional resumption" of talks with North Korea. He said there were "no prospects as to when they will return, but time is slipping by and this only worsens the situation."

Japan's defense minister, Yoshinuri Ono, said nuclear proliferation was a "major challenge for the international community not just a threat" to Asia.

The Bush administration has demanded that North Korea halt development of nuclear weapons and wants the communist country to drop its opposition to resuming negotiations with China, Russia, Japan, South Korea and the United States.

"The North Koreans are continuing to bring about their own isolation by not dealing with this problem," Rice said.

"The international community has been concerned with this for quite a long time. It is really time for the North Koreans to take seriously that concern, return to the six-party talks and begin to address the international system's concern," the secretary said.

China has hosted three inconclusive rounds of six-nation talks since 2003. North Korea refused to attend a fourth round, scheduled for September, accusing the United States of trying to topple its government.

Reviving the stalled talks has taken on greater urgency since North Korea's unconfirmed declaration this month that it has become a nuclear power.

In a joint statement, the four officials said North Korean's nuclear program "poses a serious challenge" to international nonproliferation efforts and "represents a direct threat to the peace and stability" in Asia.

Also of concern was North Korea's missile program. The United States and Japan "decided to continue to share information with a view to maintaining preparedness for any situation," according to the statement.

Rice, noting the visit Saturday to North Korea of a top Chinese official, said she hoped Beijing would convey the message that it believes "there can be no nuclear weapons on the Korean Peninsula."

The United States has ruled out economic concessions to lure North Korea back into negotiations, but has promised not to attack the nation that President Bush called part of an "axis of evil," along with Iraq and Iran.

Regarding China's threat to use force against Taiwan, which Beijing views as a renegade province that must be reabsorbed by the mainland, Rice said the four officials talked about their "desire for cooperative relations with China, our desire to ensure that the cross-(Taiwan) Strait issues can be resolved peacefully."

"I can't think of a time when the relationship has been closer or more constructive," Rumsfeld said.

"We value that in the United States and benefit from it and certainly understand that it remains a key pillar of peace and stability in the Asian Pacific region and a benefit to the world," he said.

Rumsfeld said the meetings were "an opportunity to take stock and continue the momentum toward strengthening and transforming this important alliance."

In their statement, the officials "reaffirmed the continuing strength and vitality of U.S.-Japan security arrangements, and expressed confidence in their capacity to deter and address challenges to regional peace and stability."

In East Asia, Japan is showing a growing inclination to stand with the United States on self-ruled Taiwan, which split with China amid civil war in 1949.