Cambodian children play with dirt in their fishing community on the banks of the Mekong River in Phnom Penh

The leaders of the six nations along the Mekong River have wrapped up a summit in Kunming, China, Tuesday vowing to fight environmental degradation that is threatening their common natural resource.

At the end of the summit Tuesday, the leaders of the six nations along one of the longest and richest rivers in the world agreed to create a conservation corridor along the Mekong.

China, Thailand, Vietnam, Laos, Cambodia and Burma have promised to preserve pockets of biodiversity within their borders that are important to the river's life, such as forest reserves.

The Mekong originates from high Tibetan plateau and flows into southwest China, Burma, Laos, Thailand, Cambodia and Vietnam before merging with the South China Sea.

Much of the region's 300 million people rely on the Mekong for transportation and food. But recently, environmentalists say rapid development in some countries is damaging. China's growing number of big dams has been blamed for lower fish catches and water levels downriver.

The conservation corridor was China's idea. Prime Minister Wen Jiabao told the delegates Tuesday in Kunming, that as the fastest growing country in the region, China would remain a responsible neighbor.

In addition, he urges increased cooperation in fighting communicable diseases such as AIDS and the bird flu.

Bird flu has killed more than 30 people in Vietnam since 2003 and the virus has surfaced periodically in poultry farms in Thailand, Cambodia and China.

The countries also pledged to continue cooperation in fighting poverty in the region. On Monday, the Asian Development Bank said it would loan one billion dollars in the next five years for infrastructure development and poverty eradication.

Rajat Nag, ADB director for the Mekong area, says the region has made progress since the armed conflict in Indochina in the 1970s and 1980s. But serious problems remain.

"The greatest problem in the region is poverty and I think that must be the main objective that these countries do," he said.

The region's leaders last met in Phnom Penh three years ago. Next week, officials will meet investors in Tokyo to seek greater financing for projects in the region.