JANESVILLE, Wis. -- A live cluster bomblet and ammunition have been found in a donation dropped off at a thrift shop in southeastern Wisconsin.

An employee at the Janesville Goodwill made the discovery while conducting inventory Friday morning, according to the Janesville Police Department.

The store and surrounding area were evacuated as a bomb squad was called in to remove the small bomb and ammunition.

“Employees quickly followed safety protocols by informing store and donation center management and safety teams who then evacuated the building out of precaution for shoppers, donors and employees," Goodwill Industries of Southeastern Wisconsin said in a statement to WKOW-TV.

The store and donation center resumed operations shortly after 1:30 p.m. Friday, the statement continued.

Bomblets are part of cluster bombs which contain multiple explosive submunitions. Used during battle, the bombs can be dropped from planes or fired from the ground. Janesville police were trying to determine who left the bomblet and ammunition at the Goodwill store.

Janesville is about 76 miles (122 kilometers) southwest of Milwaukee.