From the AP:

Federal officials say a raid at a northeastern Iowa meat processing plant this week was the largest in U.S. history.

Immigration and Customs Enforcement officials say 390 people have been arrested on immigration charges after Monday’s raid at Agriprocessors Inc. in Postville. The facility is the world’s largest kosher meatpacking plant.

The raid was aimed at seeking evidence of identity theft, stolen Social Security numbers and people who are in the country illegally.

Fifty-six of those arrested have been released on humanitarian grounds; many of them have to take care of children.

Others arrested in the raid at are being held in county jails and at a converted fairgrounds.