CHONGQING/KUNMING, March 25 -- Twenty people were killed and dozens more injured in two separate road accidents in southwest China, authorities said Tuesday.

Fifteen people have died and 56 others were injured in a multiple pileup early Tuesday on an expressway section in Chongqing Municipality. The accident happened just after midnight when a truck hit an overturned coach, and vehicles behind plowed into the back of the truck at a section of the Baotou-Maoming Expressway.

In a separate accident, a minibus with 29 passengers aboard plunged down a 60 meter valley at 7:42 p.m. Monday in Huize County, Yunnan Province. The minibus was taking home guests from a wedding when it veered off the road, the county government said. Five died and 24 were injured, with four in a serious condition. The vehicle was was only permitted to carry 19 people.

The causes of the two accidents are under investigation.