Police have released surveillance video of a man they say sexually assaulted a 12-year-old girl in the Bronx.

The incident happened on East 173rd Street and Weeks Avenue in Concourse Village around 11 a.m. Sunday.

Police say the man grabbed the girl on the street and put a gun to her head before dragging her into an alley between two homes and sexually assaulting her.

The girl's neighbors say that she left her home a little after 10 a.m. to pick up groceries a few blocks away.

The girl was taken to the hospital.

The suspect is described as being a man in his early 20s, around 5'7'' tall, and weighing 150 pounds.

He was last seen wearing a black cap with a black and red colored shirt, red shorts and black sneakers. 

Anyone with information is asked to call Crime Stoppers at 1-800-577-TIPS.