A woman who stepped aside to let passengers of a rush hour J train was assaulted by a fellow rider who she accidentally bumped into, police said.

The attack happened on Monday, July 11 around 9:30 a.m. at the Broadway Junction subway station.

According to police, the 21-year-old victim bumped into the suspect as she moved aside to let passengers off the Manhattan-bound train. The suspect then pulled the victim to the ground by her hair and punched her in the face several times.

The victim suffered a concussion as a result of the beating, police said.

Authorities describe the suspect as a black female, 20 to 25 years old, 5 feet 5 inches tall and with a thin build. She was last seen wearing a black top, a black and white print skirt, and flip flops.

Anyone with information should call the NYPD Crime Stoppers hotline at 800-577-TIPS or, for Spanish, 1-888-57-PISTA. The public can also submit tips by logging onto the  Crime Stoppers website.