The Wisconsin State Capitol Building is now open after a bomb threat led to a 90-minute evacuation of the building and grounds.

The evacuation occurred shortly before 4 p.m. on Wednesday while lawmakers in the state Assembly were in the middle of budget debate. Police cleared both the building and grounds around the Capitol square, where hundreds of people were gathering for an outdoor concert.

The state's Department of Administration says that the building was clear of any threat, but that no further details would be released because an investigation is ongoing, Fox 6 Now reported.

Department spokesman Cullen Werwie said in an email that the evacuation was due to a "credible bomb threat," which he did not further elaborate on, according to Reuters.

The concert of the Wisconsin Chamber Orchestra, featuring violinist Andrew Sords at the square grounds, proceeded as planned after authorities cleared the area.