A railway tunnel under construction collapsed and killed seven workers in northern China's Inner Mongolia region, a safety official said Tuesday.
Another three workers were injured in the accident Monday afternoon and were in stable condition in a local hospital, according to an official with the Work Safety Bureau in the city of Chifeng.
The cause of the accident was still under investigation, said the official, who would only provide his surname, Yue, because he was not authorized to speak to media.
The tunnel is part of a 175-mile (280-kilometer) line connecting Chifeng in Inner Mongolia to Jinzhou in the neighboring province of Liaoning.
Deadly accidents are common on Chinese construction sites as the country races to build highways, airports and subways to undergird the rapidly growing economy.