A woman was groped by a man on a CTA Blue line train Sunday night in Irving Park neighborhood on the Northwest Side.

The 25-year-old woman told police that an unknown man sat behind her on the train and then reached forward and touched her in the area of her buttocks and hips, Chicago Police said.

The incident occurred at 11:52 p.m. in the 3600 block of West Addison, while the woman was traveling between Irving Park and Addison, police said.

The woman exited the train after the incident and refused medical attention, police said.

No one was in custody.