The United States will crack down on employers who hire illegal immigrants, Homeland Security Secretary Michael Chertoff said Thursday, as agents arrested illegals in Utah and across the nation.

In Utah, Immigrations and Customs Enforcement Assistant Special Agent in Charge Joe Romel said 13 illegal immigrants were arrested this week at the Tooele IFCO Systems North America Inc. facility.

It's part of a nationwide investigation into the company that led to arrests of some 1,187 undocumented employees, along with seven current and former managers facing federal conspiracy charges.

Romel said the timing of the arrests and Thursday's announcements about the crackdown were likely a coincidence, because the national investigation into IFCO has been ongoing for more than a year.

Chertoff said the new interior enforcement strategy being used by ICE is aimed at "unscrupulous employers" and "exploitation" by smugglers.

The move, Romel said, will likely lead to more investigations into employers.

"We are looking more at employers who are guilty of harboring and providing documents," Romel said. "There are several businesses out there."

The managers were charged with conspiring to transport, harbor and encourage and induce illegal aliens to reside in the United States for commercial advantage and private financial gain. The charge carries a penalty of up to 10 years in prison and a $250,000 fine for each alien. Two other employees are facing charges related to fraudulent documents.

No managers of the Tooele site, with a total staff of 20, face charges, Romel said. Of the 13 immigrants placed in deportation proceedings, four had prior deportation orders.

The German-based IFCO, with U.S. headquarters in Houston, is the nation's largest pallet services company. A statement released by the Tooele facility said managers were cooperating with ICE agents and "hope to have this matter resolved as soon as possible."

"IFCO Systems is proud to be an equal opportunity employer and is committed to creating a workplace free from discrimination," the statement said. "It is our policy to comply with all federal and state employment requirements."

A government affidavit alleges that more than half of the Social Security numbers on IFCO's payroll in 2005 were either invalid, did not match the name attached to the number or belonged to children or deceased individuals.

The IFCO investigation started in February 2005 when ICE agents received information that workers in Guilderland, N.Y., were seen ripping up their W-2 tax forms and an assistant general manager had explained the workers were illegal immigrants, the affidavit said.