A tornado has killed 51 people and destroyed a large number of buildings in the eastern province of Jiangsu, according to Chinese state media.

The reports said the tornado formed near the city of Yancheng on Thursday. They said large numbers of people were injured and roads were blocked.

Southern and eastern China have experienced weeks of torrential rain and storms that have caused widespread flooding and a number of casualties.

CCTV showed people carrying the injured to hospitals, cars and trucks flipped over on their roofs, street light poles snapped in half, and steel electricity pylons crumpled and lying on their side.

The Jiangsu provincial fire and rescue service provided no word on casualties but said on its microblog that the storm was accompanied by hail. Photos posted online showed a wrecked three-storey schoolhouse with large trees strewn on its playing field.

The southern part of the country is hit every year during the monsoon season of May, June and July, but this rainy season has been particularly wet. Water levels in some major rivers have exceeded those of 1998, when China was hit by disastrous floods that affected 180 million people, according to state media reports.

Jiangsu is a coastal province north of Shanghai. Yancheng is an ancient city with more than eight million people.

Bodies were shown lying in the open or buried in rubble. At least one hog farm was hit, its livestock covered in bricks and roofing material.

The reports said the tornado struck at about around 2.30pm local time and hit the Funing and Sheyang counties on the city's outskirts the hardest with winds of up to 78 mph.

Tornados occasionally strike southern China during the summer months, but rarely with the scale of death and damage caused by the one on Thursday.

This year, southern and eastern China have experienced weeks of torrential rain and storms that have caused widespread flooding and dozens of casualties.