Much of China is in the grip of a summer heatwave, and the China Meteorological Association issued a high temperature warning for several eastern and central provinces, saying temperatures could reach 41 degrees Celsius (106 Fahrenheit) on Wednesday.

Leng Guangming, a spokesman at the Shanghai Municipal Centre for Disease Control and Prevention, said there had been at least 10 victims of heat stroke up to last Friday in the city. He declined to give a more precise or more recent number.

City forecasters said temperatures were "rising rapidly" and could reach 40 C in People's Square on Wednesday.

Experts blame a subtropical high pressure system and a lack of rain for the record-breaking heatwave, according to state media.

Pictures have shown people sheltering from the heat in air-conditioned shops or subways, and trying to cool off in swimming pools and rivers.

Footage of a slice of pork cooked through in 10 minutes on outdoor stone slab, taken by a Shanghai TV station, has gone viral online.