About 1,000 people in Postville, Iowa, on Sunday demonstrated at the entrance to a kosher meatpacking plant that was raided in May by immigration authorities.

Hundreds of illegal immigrants were rounded up in May at the kosher meatpacking plant in Iowa, and the two supervisors were arrested on criminal immigration charges.

In the biggest workplace immigration raid this year, federal agents swept into a kosher meat plant on Monday in Postville, Iowa, and arrested more than 300 workers.