HANOI: China today said it was cooperating with Vietnam on flood control and prevention, as Vietnamese authorities raised concerns about a major river's levels rising from a discharge of water from Chinese hydropower plants.

Vietnam has for days been battling landslides and floods caused by Typhoon Yagi, Asia's most powerful storm this year, which swept the country over the weekend and has left more than 150 people dead according to preliminary estimates.

The foreign ministries of the two countries said they have been cooperating to reduce risks on the main stream of the Red River, the largest in northern Vietnam, which is currently flooding the capital Hanoi.

But authorities in Ha Giang City close to the Chinese border warned today that water discharged from a Chinese dam could increase levels in the Lo River, a Red River tributary, according to a document and Vietnamese state media.

Asked during a regular briefing about dams releasing water and whether Beijing was cooperating with Vietnam on the Lo River, Chinese Foreign Ministry spokesperson Mao Ning said the two countries "are maintaining close and effective communication to cooperate on flood control and prevention".

She added: "In order to support Vietnam's flood control, China's hydropower stations on the main stream of the Red River are blocking and storing water", without elaborating about the Lo River.

The Lo River joins the Red River about 80km northwest of Hanoi after crossing northern Vietnamese provinces that faced floods today.

The information was briefly reported on the websites of Ha Giang province and Vietnam's state broadcaster VTV before it was taken down.

Vietnam has a tricky balancing act in managing its relations with giant neighbour China, wary of the need to preserve trade links vital to its economy and the close ties forged by their ruling Communist Parties.

Nguyen Hoang Hiep, Vietnam's deputy agriculture minister, later confirmed water had been discharged from Chinese dams today afternoon, but said the impact on Vietnam would be minimal.

"China sent Vietnam a written notice beforehand so we can make preparation," Hiep told a government news portal.

"The discharge volume is also small. It will have an impact, but not much on the downstream of Vietnam."

  - Reuters