The files posted "appear to come largely from a single shared network drive" used by the Parks and Recreation Department, St. Paul Mayor Melvin Carter said on Monday evening.

Bill payment information, like credit card numbers, is generally handled by “cloud-based” applications and should not have been affected by the hack, the mayor said.

The city of St. Paul said over the coming days, around 3500 employees will begin the process of scrubbing their data in the aftermath of the city's cyberattack.