The stabbing happened at 11:37 local time (03:37 GMT) at Zhenxiong People's Hospital in Yunnan province, the police said. 

Images published by China's The Paper showed a man in black, wielding knives in both hands, inside the hospital.

Police said the suspect is from Poji town in Zhenxiong. It was unclear if he has was arrested.

State media reports earlier said 23 people were injured, but officials have revised the toll downwards.

"At present, the injured are receiving treatment in the hospital. Investigations are ongoing," police said in a statement.

Footage on The Paper also showed police vehicles and at least a dozen police officers outside the hospital. The entrance to the hospital's carpark appeared to have been cordoned off.

"The situation is still quite chaotic, they're still determining the numbers. The police are working on it," a local resident told The Paper.

Authorities have told residents and merchants in the neighbourhood to "lock their doors" and "avoid contact with unknown persons", according to Chinese news outlet Hongxing News.