SAN FRANCISCO -- A man struck and killed by a MUNI trolley has been identified as 55-year-old Michael Mendez, authorities said Sunday.

Mendez died Saturday afternoon around 2:37 p.m. when the trolley collided with him at Market and Powell streets, police said. The San Francisco Medical Examiner's office did not release a hometown for Mendez, and witnesses told KGO-TV that he was homeless.

Officers found Mendez on the tracks when they arrived, and he was pronounced dead at the scene. Police said he was struck by an outbound trolley.

The Powell Street MUNI station was closed for several hours during the investigation and transit operations were rerouted in the area. A station agent aboard the train was treated for minor injuries at San Francisco General Hospital.

Staff writer Katie Nelson and KGO-TV contributed to this story. Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.