China will release more water from a dam in its southwestern province of Yunnan to help alleviate a drought in parts of Southeast Asia, China's Foreign Ministry said, following an initial release begun last month.
The water already began being released on Monday from the Jinghong dam, and will continue to be released until the "low water period" is over, ministry spokesman Lu Kang told a daily news briefing.
The actual amount of water released will be decided upon by how much water there is to release upstream and the demands of downstream users, Lu added.
China's releases of water show the effectiveness of "water facilities" in helping control floods and address droughts, he said.
China has said that the water released will benefit Cambodia, Laos, Myanmar, Thailand and Vietnam.
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In Vietnam, some 1.8 million people are facing water shortages and the government says 230,000 hectares (568,000 acres) of rice has been destroyed in the central and southern regions this year.
While China and Vietnam are involved in an increasingly bitter territorial dispute in the South China Sea, the two Communist-lead countries have traditionally had close ties.
Beijing and Hanoi have also been trying to repair ties severely harmed in 2014 when Beijing parked an oil rig in waters off the Vietnamese coast, leading to anti-China riots.
Thailand is facing its worst water shortage in two decades, with 14 out of 76 provinces hit and large swathes of agricultural land at risk.