Updated

Secretary of State Colin Powell acknowledged widespread anti-American sentiment in South Korea and said Sunday the United States will have to do a better job of demonstrating the benefits of the alliance between the two countries.

Winding up a 24-hour visit to Tokyo, Powell told a news conference there are South Koreans who do not remember the half-century history of U.S.-South Korean ties.

The alliance "created conditions for solid economic growth that has brought South Korea clearly into the camp of democracy," Powell said. "They have benefited greatly from this alliance."

He added that there are "always stresses and challenges in a relationship, and that certainly is the case with South Korea, but I think the relationship certainly remains strong."

Anti-American sentiment was evident during the recent presidential campaign in South Korea, particularly among younger South Koreans, despite an apparent growing military threat from North Korea.

Powell took satisfaction in noting that a large pro-American demonstration is planned in South Korea in the coming days.

He pledged the United States "will do nothing that is not in the closest of coordination with our South Korean friends."

Shortly after his arrival in Tokyo Saturday, Powell and Japanese Prime Minister Junichiro Koizumi shared concerns about North Korea's nuclear weapons and missile programs. They agreed to coordinate efforts to deal with the problem, officials said.

Powell, who also met with Foreign Minister Yoriko Kawaguchi, is on his first visit to East Asia since North Korea acknowledged in October that it was developing uranium-based nuclear arms.

The talks come at a high point in U.S.-Japanese relations. Japan backs American policy in Iraq, and has dispatched or promised to send military vessels in support of the U.S. anti-terrorism campaign in South Asia.

State Department spokesman Richard Boucher said the discussions in Tokyo showed that both sides "understand the threat posed by Saddam Hussein." On North Korea, Boucher said there was agreement on the need for close coordination and "on continuing our efforts to seek a peaceful solution."

Powell was stopping in China on Sunday and will attend the Tuesday inauguration of South Korean President-elect Roh Moo-hyun.

Japan, an avowedly pacifist country since the end of World War II, began taking a more assertive stance following a North Korean missile test that overflew Japan in 1998. At present, North Korea is believed to have dozens of missiles capable of hitting any target in Japan.

Japan has said it will use force if it has reason to believe North Korea is planning a military strike against it.

Powell noted during his flight to Tokyo that Japan has responded to North Korea's nuclear weapons buildup by suspending deliveries of food aid and slowing moves to establish normal relations.

In contrast, the United States is continuing food shipments to North Korea. Powell said Friday an announcement of a new donation will come shortly.

Cash transfers from North Koreans in Japan to their homeland are a major source of income for the North. Japan has shown no inclination to interrupt these transfers.

Assistant Secretary of State James Kelly said in recent congressional testimony that the United States stands ready to build "a different kind of relationship with North Korea" once the North eliminates its nuclear weapons program in "a verifiable and irreversible manner."

The Bush administration is worried about North Korea's plans to develop uranium-based weapons. Of greater concern is the North's potential to produce in the next few months several plutonium-based bombs that would supplement the one or two such bombs the CIA believes the country now possesses.

The administration has waged a somewhat lonely struggle to set up what Powell calls a "multilateral dialogue" with the North Koreans. It would involve China, Japan, South Korea, Russia and perhaps other countries.

North Korea has shown no interest in such an approach, calling instead for talks with the United States aimed at reaching a nonaggression treaty. Regional countries also seem to favor direct dialogue between the United States and North Korea.