LANZHOU - Five construction workers were buried in a tunnel collapse on Wednesday afternoon in northwest China, local work safety supervision authorities said.

Around 2:30 p.m., a collapse occurred at the construction site of a railway tunnel in Lanzhou, Gansu Province, according to the provincial safety supervision bureau.

A preliminary investigation revealed that five people were trapped at the scene of the accident.

Rescuers rushed to the site and have started to dig into the tunnel.

The cause of the accident is under investigation.