Chicago police are asking for the public's help to identify a man they said committed an armed robbery on a CTA Orange Line train early Saturday morning.

Mass Transit detectives said the incident happened around 12:30 a.m. on the train in the 4600 block of West 59th Street, near the Midway stop.

They said the suspect approached a passenger inside a train car with a bottle in hand and demanded their cell phone.

The suspect is described as an African American man between 20 and 30 years of age, standing between 6 feet and 6 feet 2 inches tall, weighing about 180 pounds, with short hair, and with possible tattoos on both arms.

He was last seen wearing a light-colored jersey with the words "Wild One" and the number "13" on the front, and the word "trouble" and two panther faces on the back, black-colored pants with wording "Nah I'm good" in white lettering on the upper left leg, and black-colored gym shoes.

Anyone with information about the incident or his whereabouts is asked to contact Mass Transit detectives at 312-745-4447 or submit an anonymous tip at CPDTIP.com, using reference No. JJ535792.