A Wisconsin police chief says no threats had been received by a Planned Parenthood clinic in eastern Wisconsin where a small homemade explosive caused minimal damage over the weekend.

Grand Chute Police Chief Greg Peterson says a bottle containing a chemical was placed on the clinic's outside window sill about 7:40 p.m. Sunday. A small fire broke out when the bottle exploded, but quickly burned itself out.

Planned Parenthood of Wisconsin CEO Teri Huyck (HEYEK) says there was minimal damage to an exam room and that the clinic will reopen Tuesday. No one was in the building at the time.

The Grand Chute Fire Department responded to the clinic's fire alarm and alerted police after finding the bottle.

Peterson says the FBI is helping investigate. No suspects are in custody.