Four people were killed in a 53-vehicle pileup on the Kunming-Chuxiong highway, Yunnan province, at 6:10 am on Monday.
Three were injured in the pileup with more than 80 stranded near the scene, Kunming's Xishan district government said in a statement on Sina Weibo on Monday.
Occurring along the Bijiguan section of the highway, the accident was caused by road ice as a result of extreme weather conditions and a low of -4 C in recent days, according to preliminary investigation results performed by Kunchu traffic police and local police.
The four deceased, according to the government's news release, fell to their deaths when attempting to climb over barriers between two separated sections on a bridge.
The three injured motorists, confirmed to have minor injuries, are now receiving treatment in hospital.
A traffic suspension caused by the accidents was ended at noon, said the government.
Emergency rescue operations were performed by authorities of Xishan district and Kunming city. Supplies including blankets, bread and bottled water were given to stranded motorists, and medical care was made available.
The district government said that rescue work is under way while the accident is under further investigation.
No more details concerning the accidents and people injured or deceased were released by the government.