Image caption The blast in Qingdao is the latest in a series of industrial accidents in China

At least 44 people in China have been killed in an explosion after a leaking oil pipeline caught fire in the city of Qingdao, state media has reported.

Xinhua quoted officials who said workers were trying to repair the pipeline at the time of Friday's blast.

Pictures of the scene showed shattered concrete slabs and black smoke rising. More than 100 firefighters were involved in putting out the fire.

The pipeline is owned by Sinopec, China's largest oil refiner.

The leak was spotted early on Friday, and the explosion happened several hours later, the Qingdao government said on its official microblog.

"We will investigate the incident with responsibility and give timely reports," Sinopec said in a statement quoted by the Associated Press news agency.

Image caption More than 100 fire fighters tried to douse the fire after the pipeline explosion

Image caption The explosion damaged cars and the road in Qingdao, east Shandong province

Image caption It was not immediately clear how many people were injured in the blast

Image caption The pipeline is owned by Sinopec, which is the biggest oil refiner in China

A man quoted by Xinhua said he had only seen something similar to the blast "in a disaster film".

The authorities have ruled out terrorism but say the incident remains under investigation.

Correspondents say that the blast ripped roads apart, turned cars over and sent thick black smoke billowing over the eastern coastal city.

Reports say that the number of dead could rise - at least 136 people were injured.

Because the scene of Friday morning's explosion was close to the coast, barriers were been erected to stop oil leaking into the sea, reports said.