Japan and five Mekong countries in Southeast Asia agreed Saturday to step up cooperation to protect the environment and tackle climate change over the 10 years from next year with Tokyo promising more technical assistance for the efforts.

Japanese Prime Minister Yukio Hatoyama and his counterparts from Cambodia, Laos, Myanmar, Thailand and Vietnam embraced the initiative in the Tokyo Declaration, adopted on the second and final day of the first summit meeting involving the six countries.

In hosting the event for the countries in the Mekong River region, which is rich in natural resources, Japan is believed to be angling for greater influence amid China's growing presence there.

"We shared the understanding that we will build partners for the future of common prosperity," Hatoyama said at a joint news conference after the meeting. "Regional cooperation is proceeding to address gaps in the region, and what sort of role Japan plays in that connection is very important."

The initiative, dubbed "a decade toward the Green Mekong," is the embodiment of the "Hatoyama Initiative," proposed by the Japanese leader in September to provide financial and technical assistance to developing countries that are working on cutting greenhouse gas emissions.

To encourage the region's further development, Japan pledged more than 500 billion yen in official aid to the countries over the next three years from fiscal 2010, which begins next April.

Japan and the Mekong countries also agreed that the region should aim to contribute to the integration of the Association of Southeast Asian Nations and to the building of an East Asian community in the long term.

The creation of such a community is a vision Hatoyama has eagerly promoted, and he reiterated Saturday that the Mekong countries -- most of them lag behind other ASEAN members -- would form part of his regional bloc initiative.

"In the meeting, I said that in some respects, the Mekong region holds the key to the realization of the East Asian community that I have been advocating," he said.

The declaration, which was adopted along with a 63-point action plan, spelled out continued assistance in enhancing both "hardware" and "software" infrastructure in the region. With regard to the software, Japan pledged to implement various skill enhancement programs, including customs clearance training that would help make more efficient use of roads and bridges in the region.

Japan also promised to invite about 30,000 people, mostly the young, from the region over the next three years through seminar and exchange programs to facilitate human exchanges.

The 10-year green initiative will involve reforestation, the preservation of biodiversity and the management of water resources in the Mekong River system as well as efforts to tackle climate change.

Concrete plans are expected to be hammered out when senior government officials of the countries meet in the first half of next year.

On Myanmar, which remains under military rule, Japan and the Mekong countries, including Myanmar itself, declared that they expect it to take more positive steps toward democracy.

The countries said they believe that the general elections planned in the country next year would be democratic with the participation of all political parties.

The declaration did not address Aung San Suu Kyi, Myanmar's pro- democracy leader, who has been detained in the country for 14 of the last 20 years.

But in a bilateral meeting, held on the fringes of the Japan-Mekong summit, Hatoyama pressed Myanmar Prime Minister Gen. Thein Sein to set her and other political prisoners free before the elections.

Japan and the Mekong countries urged North Korea to fully comply with U.N. Security Council resolutions punishing Pyongyang for its nuclear and ballistic missile activities and to return "immediately and without preconditions" to the six-party talks aimed at denuclearizing the Korean Peninsula.

At the news conference, Hatoyama ruled out the view that Japan is competing with China for greater influence over the Mekong region.

"Japan and China are in fact cooperating and discussing how we could best improve our cooperation for the Mekong," Hatoyama said.

"It's not a matter of China working more for the Mekong, and that it will therefore be disadvantageous for Japan," he said. "That's not the point."

In the declaration, Japan and the Mekong countries decided to hold the summit meeting every year and make the meetings of foreign ministers and economy ministers similarly regular events.

Besides the Myanmar leader, Hatoyama also met bilaterally with Laotian Prime Minister Bouasone Bouphavanh, Vietnamese Prime Minister Nguyen Tan Dung, Cambodian Prime Minister Hun Sen and Thai Prime Minister Abhisit Vejjajiva later in the day.

In the meetings with his Cambodian and Thai counterparts, Hatoyama expressed concern about a diplomatic spat between the two neighbors, according to a Japanese official. Abhisit expressed his appreciation for the concern and said Bangkok wants to keep the situation from worsening.

On Thursday, Thailand and Cambodia recalled their ambassadors from each other's countries after Phnom Penh appointed former Thai Prime Minister Thaksin Shinawatra as an economic advisor.