CHENGDU - A fuel tank truck burst into flames on an expressway linking Chengdu with Chongqing in southwest China on Friday afternoon, leaving seven people dead and four injured, a road safety watchdog told Xinhua.

The accident occurred at 3:55 pm when a tank truck loaded with industrial chemicals crashed into four other cars. Three vehicles caught fire after the crash, including the truck, a car and a van, according to the Safety Supervision Bureau of Sichuan Province.

Rescuers and firefighters rushed to the scene shortly after the accident, extinguishing the fire and clearing the site.

The four injured have been sent to hospital and traffic has returned to normal.

The cause of the accident is still under investigation.