WORTHINGTON, MINN. - An early morning raid Tuesday shut down the nation's No. 2 meatpacker, as federal agents launched a six-state hunt for illegal workers who allegedly used stolen identities to get hired.

The raids targeted six plants of Swift & Co., including the pork-processing facility that employs 2,300 in Worthington, Minn., in what the U.S. Immigration and Customs Enforcement termed "a large identity theft scheme that has victimized large numbers of U.S. citizens and lawful residents."

Officials wouldn't say how many arrests were made in Worthington, but plant workers said that at least 400 were detained Tuesday morning out of a first-shift workforce of about 1,000.

Witnesses saw 10 buses lined up to take people away, said Alondra Espejel of the St. Paul-based Minnesota Immigrant Freedom Network.

The raid began about 8 a.m., witnesses said. The "kill floor" was shut down at 10:30 and workers were taken to the cafeteria.

The detainees were later bused to federal detention centers in Sioux Falls, S.D., and Iowa.

Teresa Ramirez, 42, a legal immigrant, said she saw some workers at the plant bound with plastic cuffs and heard women screaming about who would pick up their children. She said she was not detained.

"Truthfully speaking, they treated us like trash," said Veronica Carabantes Maravilla, 33, whose daughter had to bring her green card to the plant.

"They treated the legals and illegals alike," Maravilla said through an interpreter.

Action criticized

The raids were denounced by Swift and by worker and immigrant advocacy groups as an attack on civil liberties.

And in Worthington, a city of 12,000 in the state's southwestern corner, the raid spread panic in homes and schools, where about 39 percent of the students are Hispanic and many are children of Swift workers.

A school bus driver dropped five children off at Communidad Cristiania de Worthington Church when no one answered the doors at their homes, said the Rev. Hector Andrade, the church's pastor.

Other parish members were at the church Tuesday evening to help the children. "They're just crying," said Andrade, who said volunteers were going door to door to check for more children whose parents may have been detained.

Andrade said people were coming to the church to take shelter because they don't feel secure at home.

"Right now they don't trust anybody," he said.

Detained workers will be released if they are sole caregivers, said Tim Counts, a Minnesota spokesman for the Immigration and Customs Enforcement.

The agency set up a toll-free phone number (1-866-341-3858) staffed by English and Spanish speakers to offer information on people who may have been detained.