Flooding in northeastern China has washed more than 1,000 barrels containing explosive chemicals into a major river, state media said on Wednesday.

The incident happened along the flood-swollen Songhua River in Jilin city in Jilin province in the late morning, the official Xinhua news agency said.

Residents contacted by telephone said water supplies had been cut off for a time in parts of the city, but were starting to return to normal.

The containers, from a chemical plant, held more than 160,000 kg (352,700 lb) of explosive chemical fluids, Xinhua said, citing local officials.

'Emergency workers have been trying to recover the containers and local environmental protection authorities were closely monitoring the water quality of the river,'  the report said.

China periodically faces spills into rivers that result in water supplies being cut off, most seriously in 2005 when an explosion at an industrial plant sent toxic chemicals streaming into the Songhua River further upstream, in Harbin.

The incident forced the shut-down of water supplies to nearly four million people.

Rains so far this year across large swathes of central and southern China have killed more than 700 people and left hundreds of others missing.

Northeastern China has also been lashed by torrential rains over the past few days. – Reuters