20 killed in tunnel blast

Latest: Twenty people were killed in an explosion inside an under-construction expressway tunnel in central China's Hunan province Saturday, local authorities said.

CHANGSHA - Twenty people are still being trapped inside an under-construction expressway tunnel in central China's Hunan province that was ripped through by a blast of explosives Saturday morning, local authorities said.

Four workers have been pulled out of the tunnel, including one in critical conditions. Rescuers are searching for survivors with a life detector.

The blast happened in Yanling county, Zhuzhou city, on an expressway linking the counties of Yanling and Rucheng, when a vehicle carrying explosives was unloading in the tunnel.