Vietnam battles severe floods after deadly Typhoon Yagi

Vietnam battled serious flooding in the wake of Typhoon Yagi on Monday, as business leaders said the storm had been a "disaster" for the country's vital manufacturing sector.

Yagi, the most powerful typhoon to hit northern Vietnam in 30 years according to meteorologists, downed bridges, tore roofs off buildings and damaged factories after making landfall on Saturday carrying winds in excess of 149 kilometres per hour.

Power blackouts and flooding caused major disruptions to factories in northern Vietnam, which is a major production hub for global brands such as Samsung and Foxconn.

The storm killed 21 people in Vietnam, state media reported, while authorities said on Monday that 247 people had been injured.

At least 24 more were killed as Yagi tore through southern China and the Philippines before hitting Vietnam.

Some 1.5 million people were still without electricity in Vietnam on Monday and a major bridge across the swollen and fast-moving Red River collapsed in northern Phu Tho province.

Pictures on state media showed half of the 375-metre Phong Chau bridge gone.

Deputy Prime Minister Ho Duc Phoc estimated 13 people were missing, according to state news site VNExpress.

He said there were 10 cars and trucks, along with two motorbikes, on the bridge when it collapsed.

In the neighbouring province of Yen Bai, 2,400 households were forced to move to higher ground as the water level rose to dangerous levels.

Floodwaters reached a metre (three feet) high in parts of Yen Bai City on Monday.

Disaster authorities said 130 locations in 17 cities and provinces across Vietnam's north were at high risk of flooding and landslides.

Across northern Vietnam, 5.7 million people customers were hit by power blackouts on Saturday and Sunday, according to state utility EVN.

Vietnam is a crucial part of the supply chain for some of the world's most important companies and many key domestic and foreign-owned factories are located in the north.