At least 43 people have been confirmed dead and four were injured in a rear-ending accident that resulted in a fire and explosion in Hunan province on Saturday morning.

The accident happened at around 3 am on a section of the Hukun (Shanghai to Kunming) Expressway in Longhui county when a freight van loaded with flammable liquid rear-ended a passenger coach, which was heading from Putian city, Fujian province, to Yibin city, Sichuan province.

There were 55 people, including two drivers, in the coach, which was not legally allowed on the road overnight when the accident happened. According to Chengdu Commercial Daily, most of the passengers were from Yibin.

The driver of the illegally modified van and one passenger in it were killed at the scene. The fire had been put out at 8 am, and traffic gradually returned to normal in the afternoon.

The crash and explosion destroyed a total of five vehicles. The injured have been rushed to a local hospital for emergency treatment, said Wu Xianyun, a publicity official of the provincial government.

A joint team led by senior officials with the State Administration of Work Safety, the Ministry of Public Security and the Ministry of Transport has arrived at the site for rescue and investigation.

Hunan's governor Du Jiahao and vice-governor Sheng Maolin have also arrived at the scene.

Shi Shiping, a villager living near the scene, told Xinhua News Agency that he "heard a huge bang" when the accident happened. "It was like the explosion of an atomic bomb," he said.