WATERLOO, Iowa — Law enforcement officials are warning motorists to use caution on rural roads in northeastern Iowa following a series of sex assaults on women.

The Black Hawk County Sheriff’s Office says in a news release that several women have reported being assaulted on rural roads in Black Hawk, Linn and Tama Counties.

The Linn County Sheriff’s Office says the latest case is a woman who reported being attacked early Friday morning by a man who flagged her down on a rural road near Bertram. Investigators say when she got out of her car to help, he pushed her against his car and sexually assaulted her.

Sheriff’s officials are asking motorists to report anyone sitting along a road or highway in the area. Motorists who have a vehicle break down are urged to call law enforcement if they feel unsafe.