OMAHA, Neb. (AP) — A large federal law enforcement operation has targeted businesses in Nebraska and Minnesota that officials say knowingly hired — and mistreated — immigrants who are in the U.S. illegally.

The investigative arm of U.S. Immigrations and Customs Enforcement led the operation Wednesday that saw 14 business owners and managers and 130 workers arrested. Most of the arrests were in northern Nebraska and southern Minnesota. Homeland Security Investigations special agent in charge Tracy Cormier described the operation as one of the largest in its 15-year history.

Cormier says the focus of the operation is a business that knowingly offered for hire immigrants in the country illegally to other businesses, including farms, meat processors, grain companies and restaurants. Cormier says owners and operators of those businesses that hired the immigrants also were targeted for arrest.