A section of China's longest river, the Yangtze, has been closed to navigation as flood waters surged through the site of the massive Three Gorges dam project.

The official China Daily newspaper said river traffic was halted in the central province of Hubei as water volumes were expected to rise to a near record rate of 46,000 cubic metres per second.

Official estimates say the annual flood season in south-west China has killed more than 130 people across several provinces in the past few days, with millions affected by washed-away houses and ruined crops.

Local media said 52 people were now known to have died and 41 were missing in a massive mudslide which engulfed villages in the south-western Yunnan province on Wednesday.

Vietnam, too, has been hit by floods and landslides, with at least four people killed and more than 20,000 evacuated.

The key coffee-growing province of Daklak is one of the worst-affected areas, although local officials say crops have not been affected.

Heavy rains

China Daily said the province worst affected by the floods was Hunan, where hundreds of thousands of people live behind dykes on land reclaimed from drained lakes and smaller rivers.

Heavy rains have also been battering Sichuan province and the city of Chongqing - upstream of the Three Gorges site - and Yunnan, where tobacco crops have been washed away.

The mudslide struck Xinping county to the south of the provincial capital of Yunnan, Kunming, early on Wednesday morning - after days of torrential rains.

It followed a huge slide on Monday in the north of the province which left at least 16 people dead.

So far this year, nearly 1,000 people have been killed in storms and flooding in China, while at least 17 have died in Vietnam since the end of July.

Man also to blame

The BBC's Beijing correspondent, Rupert Wingfield-Hayes, says the landslides are being blamed on heavy downpours.

But he says there is little doubt that man is also to blame. Mountain sides have been stripped of dense forests that kept soil in place to make way for cultivation of tea, coffee and tobacco.

China's northern provinces, in contrast, are suffering a severe drought, threatening millions of farmers and large areas of crops.

Many rural households have had no rainfall since late July.