A Chicago man was robbed at gunpoint on Sunday afternoon near the CTA Green Line in Oak Park.

Oak Park Police reported around 2:50 p.m. Sunday a man wearing black jeans, black hoodie and black shoes approached a 24-year-old Chicago man walking at the 100 block of N. Humphery Avenue and displayed a semi-automatic handgun.

He then directed the man under the viaduct at Humphery and North Boulevard, placed him in a headlock and said “What you got?”

Oak Park Commander LaDon Reynolds said the man was then hit over the back of the head with the handgun.

The man then relinquished his 80- gigabyte Apple iPod, Reynolds said, and the offender fled on foot.

“The victim reported a second subject across the street appearing to be a lookout,” Reynolds said.

Reynolds said the Chicago man sustained minor injuries but was not hospitalized and refused an ambulance.

“The case is currently under investigation,” Reynolds said.

In early January, Oak Park and Chicago Police warned commuters of a string of robberies that occurred along CTA Green and Blue lines.

bdoyle@tribune.com