An international conference has begun in Thailand to discuss a crisis over water levels on the Mekong River, which is at its lowest level in 50 years.
Local communities in northern Thailand and Laos say Chinese dams, built further upstream, are to blame for the shortage of water in the river, on which more than 60 million people depend.
The Chinese government denies this, and says unusually low rainfall is to blame, as the region suffers a crippling drought.
China is itself suffering the worst drought in a century in its southwest, with more than 24 million people short of drinking water.
Beijing's Vice Foreign Minister Song Tao will join the premiers of Cambodia, Thailand, Laos and Vietnam at the two-day summit in Hua Hin on Sunday.