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.

"Employers and workers alike should be on notice that the status quo has changed," Chertoff said in a statement. "These enforcement actions demonstrate that this department has no patience for employers who tolerate or perpetuate a shadow economy."

The internal enforcement plan announced Thursday is the second phase of the Secure Border Initiative, a multi-year plan to secure the nation's borders and reduce illegal migration. The first phase remains focused on securing the borders.

Its goals include identifying and removing criminal aliens, immigration fugitives and other immigration violators, along with building strong worksite enforcement and compliance programs. It's also targeting criminal infrastructures at home and abroad that support illegal immigration, such as immigrant smuggling organizations and document and benefit fraud organizations.

The House passed legislation last year aimed at getting tough on employers who hire illegal workers and that would require employers to use a national system to electronically verify workers' legal status.

The Senate is expected to resume debate next week on legislation that would include guest worker status for undocumented workers who meet certain requirements.

Community activist Tony Yapias of Proyecto Latino de Utah said he'd received concerned calls about the crackdown all day Thursday.

"We feel that the timing is very unfortunate because national efforts are under way to work together on creating a compromise that may include a guest worker program that would allow people arrested today to come into compliance and work legally in the United States," Yapias said.

Contributing: Associated Press