Bangkok- A summit of the six countries connected by the Mekong River kicked off Sunday in land-locked Laos with a series of youth and business meetings, officials said Sunday.

The third summit of the greater Mekong sub-region countries - Cambodia, China, Laos, Myanmar, Thailand and Vietnam - started Sunday in Vientiane with meetings by a regional youth group and businessmen, Radio Laos reported in a broadcast monitored in Bangkok.

Khamthan Suthienamtha, secretary general of the Youth Union of the Lao People's Revolutionary Party, opened the meeting with the prediction that the summit would help "meet the strategic targets of the younger generation in all six countries."

"The visiting leaders met with the youth and business leaders in the afternoon," Lao Foreign Ministry spokesman Yong Chanthalangsy said.

The leaders will meet on Monday.

"The most important document expected to come out of this summit will be the Vientiane Declaration and the Vientiane Plan of Action for the Mekong," Yong said in a telephone interview.

Several bilateral agreements were signed Sunday between the visiting leaders and their Lao counterparts.

Chinese Premier Wen Jiabao arrived Saturday to attend the summit and met with Lao President Choummaly Saygnasone Sunday morning to discuss bilateral relations.

China has become a leading aid donor to Laos in recent years. Chinese companies have become major investors, especially in rubber plantations and hydroelectricity projects, in the land-locked communist country of less than 6 million people but a land mass equal to half of France.

The summit co-hosted by the Asian Development Bank is expected to mark the official opening of a 1,800-kilometre road from Kunming, in China, to Thailand's capital Bangkok.

Besides Wen, Cambodian Prime Minister Hun Sen, Vietnamese Prime Minister Ngueyn Tan Dung and Myanmar Premier General Thein arrived in Vientiane Saturday to attend the two-day summit. Thai Prime Minister Samak Sundaravej arrived on Sunday.

The bloc was established in 1992 to promote economic and social development, irrigation and cooperation within the six countries linked by the 4,200-kilometre Mekong River. (dpa)