CHICAGO (AP) — Chicago police say an officer was shot in the head during a “gun battle” on the city’s Northwest Side.

Police Department spokesman Anthony Guglielmi says the officer was struck Tuesday night during a shootout with a bank robbery suspect. The officer was taken to a nearby hospital.

Guglielmi initially said the officer only suffered a graze wound and was responsive, but the spokesman now says the bullet “did penetrate and exit” the officer’s skull and that the injuries are more serious than the preliminary diagnosis.

Chicago Police Supt. Eddie Johnson and Mayor Lori Lightfoot are expected to give more details at a press conference late Tuesday.

Police haven’t revealed information about the suspect.