Shot man fronts Sydney hospital

A man with a gunshot wound to his chest has walked into a hospital in Sydney's southwest but is not telling police what happened.

Police say the 21-year-old entered Bankstown Hospital at about 3.20pm on Friday and had undergone surgery for an injury that was not life-threatening.

The man remained in hospital under police guard but had been "confrontational and uncooperative" when officers spoke to him, police said in a statement.

Detectives are trying to determine the circumstances surrounding the shooting, including where it took place.