Seventeen people are in federal custody as part of an ongoing investigation of a Fremont meatpacking plant by immigration officials.

U.S. Immigration and Customs Enforcement spokesman Greg Palmore says they were arrested Tuesday at Fremont Beef for immigration violations.

He said Wednesday that immigration agents performed an "enforcement action" — not a raid — to determine whether Fremont Beef is complying with immigration laws.

He says no further information is available.

A message left by The Associated press for a company spokeswoman was not immediately returned.