A woman was sexually assaulted Sunday morning in the West Garfield Park neighborhood on the West Side.

About 11 a.m., the 21-year-old was walking north on Cicero Avenue from Madison Street when a man walked up and began talking to her, Chicago police said.

He then showed her a dark colored object in his waistband and ordered her to walk with him. He led her to the back of an alley in the 4600 block of West Washington where he sexually assaulted her, police said.

The attacker was described as a black man in his mid 30s to mid 40s, weighing between 140 and 190 pounds with short black hair, wearing an oversized long sleeve button-up collared shirt with yellow stains on the back, dark blue jeans and orange, gray and white Nike shoes, police said.

Anyone with information is asked to contact Area North detectives (312) 744-8261.