SEOUL, South Korea — As U.S.-South Korean war games continued Tuesday, the United States and two crucial Asian allies agreed to meet in Washington for talks about North Korea's attack on a South Korean island and the North's nuclear weapons programs.

Although North Korean rhetoric remained high — the country warned the military drills could trigger "full-blown war" — a senior North Korean official left Pyongyang for talks with leaders in the country's only major ally, China.

The visit of Choe Thae Bok, the chairman of North Korea's parliament, to Beijing, combined with the planned Washington meeting, raised hopes that a diplomatic solution could be found.

Even as Choe traveled to Beijing, however, the North reminded the world it was forging ahead with its nuclear efforts. Pyongyang said Tuesday that it's operating a modern uranium enrichment plant equipped with thousands of centrifuges. The main Rodong Sinmun newspaper said in an editorial that the North is also building light-water reactors. The commentary, carried by the official Korean Central News Agency, said the uranium enrichment is entirely for peaceful purposes.

The North first revealed the program in early November to a visiting American scientist. A light-water nuclear power reactor is ostensibly for civilian energy purposes, but it gives the North a reason to enrich uranium. Uranium enrichment would give the North a second way to make nuclear bombs, in addition to its known plutonium-based program.

North Korea has pushed for renewed international talks on receiving much-needed aid in return for commitments to dismantle nuclear programs, and its recent aggression could reflect frustration that those talks remain stalled.

The North unleashed an artillery barrage on a South Korean island Nov. 23 that hit civilian areas marking a new level of hostility along the country's contested maritime border. The attack killed two civilians and two marines.

South Korean President Lee Myung-bak took responsibility Monday for failing to protect his citizens and pledged a tough response if the North carries out any further attacks.

Foreign ministers from South Korea, the United States and Japan are to meet in Washington in early December to discuss the shelling and North Korea's nuclear program, according to Seoul's Foreign Ministry.

Despite the diplomacy, tension in the region remained high.

On Tuesday, the North's propaganda machine issued a warning that the South Korea-U.S. drills, involving a nuclear-powered U.S. supercarrier, could trigger a "full-blown war" on the peninsula.

"Our republic has a war deterrent that can annihilate any aggressor at once," the Pyongyang's government-run Minju Joson said in a commentary. "A northward provocative war means a self-destruction."

On the streets of Pyongyang, North Koreans spoke with pride of their military.

"Those who like fire are bound to be punished with fire," Kim Yong Jun, a Pyongyang resident, told international broadcaster APTN. "If the U.S. imperialists and South Korean puppets continue to gather the clouds of war, the Korean army and people will never forgive them."

A rally in Seoul drew several thousand protesters who burned North Korean flags and demanded stronger action against the communist neighbor. Another small protest of about 20 people called for calm, with a monk holding a banner reading, "Yes peace, not war!"

About 85 former South Korean special agents whose mission was to infiltrate North Korea went to Yeonpyeong Island on Tuesday and said they would stay for a week to help with reconstruction. They criticized the North's attack and urged the South Korean government to punish Pyongyang.

The U.S. ambassador to the United Nations, Susan Rice, said Monday that the U.N. Security Council is studying how to respond to the shelling as well as the recent uranium revelations.

Yonhap news agency reported that Choe, the North Korean official, will stay in China for five days and was invited by Wu Bangguo, chairman of the rubber-stamp National People's Congress.

Choe, who concurrently serves as a ruling Workers' Party secretary, was expected to meet top Chinese communist party officials and discuss last week's artillery barrage, the North's nuclear program and the U.S.-South Korean military drills, Yonhap said.

Choe visited China in late September and briefed President Hu Jintao and other Chinese leaders about the North's decision to give top political posts to a son of North Korean leader Kim Jong Il, Yonhap said.

China, North Korea's only major ally, has sought to calm tensions by calling for an emergency meeting among regional powers involved in six-party nuclear disarmament talks — among the two Koreas, the U.S., China, Russian and Japan — which have been stalled since last year.

Seoul, which wants proof of Pyongyang's commitment to denuclearization as well as a show of regret over the March sinking of a warship, reacted coolly to the proposal.

Japan rejected a new round of aid-for-disarmament talks any time soon. Foreign Ministry Seiji Maehara said in an interview with national broadcaster TBS late Monday that North Korea must first honor past commitments on disarmament.

Kim reported from Seoul. AP writers Foster Klug and Ian Mader contributed to this report.