Two dead in separate SA crashes

A man has died in a four-car crash in South Australia's mid-north while another man was killed after crashing into a tree in the Adelaide Hills.

Police say a 66-year-old man died on the Augusta Highway at Warnertown at about 5.30pm on Friday.

Another man was treated for minor injuries while the occupants of the two other vehicles involved in the crash were uninjured.

At about 6pm on Friday at Forreston in the Adeliade Hills a 61-year-old man died when his utility hit a tree.