A small, homemade bomb exploded outside a Planned Parenthood office in Wisconsin on Sunday night, prompting a federal investigation and the swift condemnation of violence by a Republican presidential candidate ahead of the state’s primary on Tuesday.

The attack took place at about 7:30 p.m. local time in Wisconsin, causing a small amount of damage to the building in the town of Grand Chute, about 30 miles southwest of Green Bay. No one was injured.