Seven people were killed in a nine-vehicle pile-up on an expressway in southwest China's Sichuan Province on Friday, local traffic police said.

Video screenshot. [Photo:China Plus]

The accident, which happened at about 4:30 p.m. on the Ya'an-Xichang Expressway, also injured 12 people, who were sent to the hospital, the province's traffic police authorities said.

The cause of the accident is still under investigation.