North Korea is showing signs of flexibility over returning to nuclear disarmament talks, and other countries must seize the opportunity to get the negotiations back on track, China's premier said Saturday.

"We need to seize the opportunity and make the most of it. This way it is possible for us to make further progress," Premier Wen Jiabao told a news conference after a meeting with leaders from Japan and South Korea.

The three leaders said they agreed on the need to work together on the nuclear issue and to jointly tackle other challenges, such as expanding trade and investment ties as they move toward greater regional integration.

Wen's comments were his first public statements on his meetings last week in Pyongyang with North Korean leader Kim Jong Il, who told him the isolated communist country may end its boycott of the talks, depending on its negotiations with Washington.

Wen said his deepest impression from 10 hours of talks with Kim was that North Korea wants to improve relations with the United States as well as Japan and South Korea.

"The North Korean side showed flexibility. It said it is not opposed to the six-party talks, and it is willing to resolve the relevant issues through bilateral and multilateral talks," Wen said.

Kim's offer of dialogue appears to reflect the North's keenness for direct engagement with Washington — a perennial demand.

The U.S. has not yet publicly responded to Kim's apparent overture. But American officials have said talks with North Korea may be possible if they are part of the six-nation disarmament negotiations that Pyongyang spurned after it was condemned for conducting a rocket launch in April and nuclear test in May.

Japanese officials said late Friday that the U.S. had indicated it might meet with North Korea.

Key to drawing the North back into disarmament talks, which involve China, Japan, the U.S., the two Koreas and Russia, are U.N. sanctions imposed after the isolated country's rocket launch and nuclear test.

On Friday, Japanese Prime Minister Yukio Hatoyama and South Korean President Lee Myung-bak said they agreed the North should not be given aid until it begins to dismantle its nuclear weapons program.

As pressure mounts on the North, the isolated country marked the 64th anniversary of the founding of the ruling Workers' Party with calls to unite around leader Kim — though there was no mention of the nuclear standoff. The anniversary of the Worker's Party — the only party to rule the North since the peninsula split — is a major holiday.

North Korea is pushing to send its deputy nuclear envoy Ri Gun to the United States later this month for a private security forum, a South Korean diplomat said. He asked not to be identified because the forum's organizers have not announced details of the session.

The planned trip raises speculation that Ri could meet with U.S. officials to lay the groundwork for possible direct talks between the two countries.

In Washington, State Department spokesman Philip J. Crowley said Friday that non-governmental organizations have invited Ri to participate in meetings in the U.S., but he said no decision has been made yet on whether to approve the visit.

Apart from North Korea, Wen and his counterparts also discussed climate change, the world financial crisis and moves to deepen already close economic and trade ties.

Despite signs of a nascent recovery, Hatoyama told reporters that cutting back on stimulus measures would be premature.

"It may be too early to consider exit strategies," he said.

Hatoyama appeared to win support for his push for a regional economic community, with the three leaders agreeing to research the idea of a free trade agreement.

Japanese officials caution, however, that Hatoyama's call for a so-called Asian Economic Community is still only a long-term vision.