Flood waters from southern China were further pushing up river levels in northern Vietnam on Tuesday, worsening inundations in a wide region that have killed at least 119 people on both sides of the land border.
Floods striking northern and central Vietnam since last Friday killed 85 people, while 34 died from flooding and mudslides in southwestern China.
On Tuesday, more rain fell in the Vietnamese capital Hanoi, where authorities reported 20 deaths from drowning, electric shock or lightning in the heaviest flooding since 1984. Schools stayed closed on Tuesday and many streets in and around the city remained submerged.
"This natural disaster is characterised as the largest ever in Hanoi," Pham Quang Nghi, chief of the Hanoi branch of the ruling Communist Party, was quoted by state media as saying at a meeting on Monday.
In southwestern China's Yunnan province, mudslides caused by heavy rain killed at least 26 people, with 45 missing, Chinese state media reported. Mountain torrents triggered by heavy rain hit Guangxi to the east of Yunnan, killing eight.
Vietnam's Health Ministry alerted all clinics in flood-hit areas to be staffed around the clock to prepare for any outbreaks of diseases such as cholera or dengue as residents in parts of Hanoi and 17 other provinces struggled with shortages of fresh water, food and power cuts.
State-run Voice of Vietnam radio said instant noodle and rice were distributed to flood victims in and around Hanoi on Monday.
More water arrived in the northern province of Lao Cai from China, raising Vietnam's Red River, the radio station said in its Tuesday morning broadcast.
Forecasters said Thai Binh river, the second main water supply for Vietnam's northern delta region, was also rising.
But Vietnam's main agricultural area, including the central highlands coffee belt and the Mekong Delta rice basket, have not been affected by the floods, although rain disrupted coffee harvesting last week.