GUIYANG - Thirteen people died and 21 others were injured, including 11 seriously, after an overloaded coach turned over and crashed along a 100-meter slope in southwest China's Guizhou Province on Saturday, local authorities said.

The accident occurred around 9 am in Congjiang County, some 450 km southeast of provincial capital of Guiyang, sources with the county government said.

Five people were killed instantly, while eight others died on their way to or in hospital.

An initial investigation showed that the coach designed for 19 passengers was carrying 34 when the accident occurred.

A further investigation into the cause of the accident is under way.