KUNMING, April 4 (Xinhua) -- Seven people died and two others were injured in an explosion in an expressway tunnel under construction in southwest China's Yunnan Province Monday evening, local authorities said Thursday.
The blast happened at around 8 p.m. on Monday in the tunnel near Weixin County, which is a section of the expressway linking Yibin City in Sichuan Province and Bijie City in neighboring Guizhou Province.
High concentration of gas inside the tunnel is suspected of having caused the blast.
Initially two people were found dead with five others unaccounted for. Rescuers searched for over 40 hours and found the bodies of the missing people on Wednesday.