In a dramatic crackdown, immigration agents showed up without warning at about 100 7-11 convenience stores around the country before dawn Wednesday, interviewing employees and managers, serving audit notices and arresting 21 workers, reports the Huffington Post. U.S. Immigration and Customs Enforcement (ICE) said the sweep was meant to ensure that employers had not hired individuals without work authorizations. The agency said the raids ― the largest operation against an employer under the Trump administration –were meant to serve as a “strong message” to other businesses to follow the law by not hiring undocumented workers. “Today’s actions send a strong message to U.S. businesses that hire and employ an illegal workforce: ICE will enforce the law, and if you are found to be breaking the law, you will be held accountable,” ICE Deputy Director Thomas Homan said in a statement. “Businesses that hire illegal workers are a pull factor for illegal immigration and we are working hard to remove this magnet.” Immigration experts told HuffPost that such highly visible workplace enforcement ― with agents showing up unannounced across the country early in the morning, questioning and arresting employees ― appears to be a show of force meant not only to keep businesses in compliance but also to demonstrate the administration’’s zero tolerance toward undocumented people. All 21 people ICE arrested were employees, the agency confirmed. “When we talk about targeting employers, that’s auditing employers to see if they followed those rules. It’s not necessary to show up with agents and interview people on site unannounced,” Angela Banks, an immigration expert and professor of law at Arizona State, told HuffPost.