The tunnel under construction in Southwest China's Yunnan province. [Photo/Chinanews.com]

Twelve people have been confirmed dead after a freeway tunnel under construction collapsed in Southwest China's Yunnan province, local authorities announced Wednesday.

Ten others who were injured are still hospitalized, and seven of them are in stable condition.

The accident occurred at around 5:21 pm on Nov 26 at the tunnel exit on a freeway in Fengqing county under the city of Lincang.

More than 700 rescue workers joined the search and rescue operations after the accident. The search and rescue work has been completed. The cause is till under investigation.