Rescuers search for injured people after a blast in Fuquan city, Guizhou province, Nov 1, 2011.[Photo/Xinhua]

GUIYANG - Seven people have been confirmed dead and about 200 others injured in an explosion that occurred near a gas station in southwest China's Guizhou Province Tuesday, local authorities said.

The accident happened at about 11:30 am, when two cargo trucks loaded with about 70 metric tons of explosives exploded in front of a motor vehicle testing station in the city of Fuquan, about 100 km from Guizhou's capital of Guiyang, according to the local rescue headquarters.

Windows shattered in nearby houses, and cars parked near the site were severely damaged. A nearby grain warehouse was seriously damaged as well.

A witness told Xinhua that the testing station was destroyed and a neighboring five-story residential building was severely damaged.

Police and rescue workers arrived at the scene swiftly after the blast occurred.

About 200 people have been rushed to a local hospital, 20 of whom are in critical condition, said a spokesman with the local rescue headquarters.

An investigation into the cause of the explosion is under way.