Chinese authorities say six schoolchildren have been killed in a stampede at a primary school in the southern city of Kunming.

Kunming's propaganda office said Friday on its microblog that more students from the first and second grades of Mingtong Primary School were injured. It does not say what caused the stampede.

Also on Friday, a man fatally stabbed four elementary school students their way to school in the neighboring province of Guanxi.

Earlier this month, a Chinese man killed three pupils on the first school day before jumping to his death in the central Hubei province.

Chinese education officials have repeatedly demanded that campus security be increased.