Seven people were killed by a torrent of water that came rushing down a river in a popular recreational spot following mountain rains in southwestern China, authorities said Sunday.

Workers and volunteers mobilized to urge people to leave the area after receiving an imminent heavy rain warning at about 2:40 p.m. Saturday, the emergency management bureau in Pengzhou city said.

People could be seen scrambling to flee in videos posted on social media, but some were caught when the torrent hit less than an hour later at 3:30 p.m.

One man at the scene said several people were washed away, including some children, when the waterflow in the lower reaches of the river suddenly increased in just 10 to 20 seconds, the state-owned China National Radio reported.

The Chengdu city government said Sunday that seven people died and three others were hospitalized with minor injuries.

Pengzhou is a tourist spot about 70 kilometers (45 miles) north of Chengdu, the capital of Sichuan province.

A video showed a helicopter rescuing a person stranded on a small outcropping by descending to just above the water and opening a door so the person could climb in.

Elsewhere in China, heavy rain flooded streets in the northwestern city of Xining on Saturday night. Heavy to torrential rain was forecast for the northeast from Sunday to Monday afternoon with 10 to 18 centimeters (4 to 7 inches) of rainfall expected in parts of Liaoning and Jilin provinces.

A heat wave was hovering over a wide swath of southern China, with highs Sunday forecast at 35 to 39 degrees Celsius (95 to 102 degrees Fahrenheit) and possibly surpassing 40 degrees (104 Fahrenheit) in some places including Shanghai.

Jiangsu province warned that road surface temperatures could rise to 72 degrees (162 Fahrenheit), raising the risk of flat tires, state broadcaster CCTV reported.