At least 65 people have been killed and 120 others injured after a factory explosion in eastern China, according to state media.

The blast reportedly occurred at 7.30am local time at the Kunshan Zhongrong workshop, which makes car wheels for US companies such as General Motors.

Footage showing large plumes of black smoke rising from the factory - which is in the province of Jiangsu - was broadcast on China Central Television (CCTV).

Other images showed the injured. some of whom were badly burnt, lying on wooden pallets and being placed in trucks and ambulances.

CCTV reported that more than 200 workers were at the site when the blast occurred.

A rescue operation is under way and authorities are working to confirm the number of casualties.

A preliminary investigation suggested the explosion was caused by negligence after a flame was lighted in a dust-filled room, state news agency Xinhua said.

Two officials from the factory have reportedly been detained.

Authorities have also established an emergency blood-donation drive in the city to assist casualties.