New York City police say a man has been arrested on charges of assault and reckless endangerment after an officer assigned to guard the mayor was struck with a pellet gun.

The 19-year-old man was arrested Monday in the assault on the officer outside Gracie Mansion, where the mayor and his family live.

The mayor wasn't home at the time.

The officer was struck in the back with a pellet Sunday night. Her injuries were minor.

Police say there's no indication the officer was intentionally struck.

Police also questioned a woman. but she has not been charged.

Investigators believe the shooter also damaged windows in the same neighborhood with a pellet gun earlier this summer.

The investigation is ongoing.