YANCHENG (China) • Villagers are scrabbling through the rubble of their homes after a tornado left at least 98 dead in China, with hundreds more injured.

Whole villages were levelled and huge trees felled when winds of up to 125kmh struck Yancheng city in the eastern province of Jiangsu on Thursday afternoon, Xinhua news agency reported.

So far, at least 98 people have been confirmed dead in the storm and more than 800 have been hospitalised with injuries, Yancheng's deputy mayor, Mr Wu Xiaodan, told a press briefing. About half of the injured were in serious condition, the Ministry of Civil Affairs said.

Chinese President Xi Jinping has ordered "all-out rescue efforts" after what Xinhua said was one of the worst disasters ever to hit Jiangsu, with hailstorms and the worst tornado to hit China in half a century.

More than 1,300 police officers had been mobilised to help in the search for survivors and the clean-up.

The wards of a hospital in worst-hit Funing county were all full, with extra beds crowding the hallways.

A factory worker with head and arm injuries and on an intravenous drip told Agence France-Presse he had been swept out of his workplace by the tornado despite clinging to a door as he tried to hold it shut against the storm.

"It all happened so fast. I have never seen anything like this before in my life," he said. "I thought for sure I was going to die. I can't believe I am still alive."

The tornado, which struck around 2.30pm on Thursday, and accompanying hailstorms destroyed tens of thousands of houses as well as several manufacturing plants and rice mills.

Tornados occasionally hit eastern and southern China during the summer months, but rarely cause extensive damage. A similar tornado disaster hit Yancheng in March 1966, killing 87 people and destroying more than 30,000 buildings. But few residents remember it.

An elderly man from Shuangqiao village told Yanfu Daily: "I'm 80 years old and I've never seen a tornado like this."

China's National Meteorological Centre admits that it could not issue warnings as it lacks the monitoring and forecasting technology.

Many mistook Thursday's tornado for a heavy thunderstorm, reported South China Morning Post.

"The skies turned dark and we thought the summer torrential rain was about to begin," a resident of Yancheng told Sina news portal, reported the New York Times.

"We ran to our house. Suddenly, the roof was blown apart, bricks were falling and the house collapsed."

Reporter Zang Shoucheng told Xinhua the gales were so strong that his grandmother had to lie down on her belly to avoid being swept away.

One picture of the aftermath showed a man who had apparently tried to shield a woman from falling debris; both were found dead in a pile of rubble.

The summer often brings severe weather to China, but rainfall has been particularly heavy this year.

South-west Chongqing municipality is the latest region to report flooding from torrential rains.