WASHINGTON -- An Obama administration policy to go after employers who knowingly hire and exploit illegal workers is not significantly different from the Bush administration strategy, according to a copy of the guidelines obtained by The Associated Press.

The new guidelines for immigration agents, which the Homeland Security Department calls a "renewed department-wide focus," will impose fines and criminal charges against employers who break the law.

While the priority is to go after employers, the policy states that agents will continue to arrest illegal workers. The Obama administration policy, however, stresses that humanitarian guidelines will be followed more broadly than in the previous administration.

The new policy was being circulated to immigration officers around the country on Thursday.

Homeland Security Secretary Janet Napolitano has said that under her leadership the agency will now be focused on "renewing a priority on employers who are making money off of these illegal immigrants and giving them jobs that should be going to American workers, as opposed to just counting numbers."

In 2008, Immigration and Customs Enforcement brought criminal charges against 135 employers and 968 workers.

In an interview with The Associated Press earlier this month, Napolitano said using investigative tools such as auditing documents employees fill out when they join a company, having illegal workers go undercover and talking to people who regularly interact with the employers are all ways to build a case against a business that hires illegal workers.

"What I want to do is deter more employers from intentionally and knowingly hiring illegal workers," Napolitano said.

Worksite enforcement operations take up only a small percentage of ICE's nearly $6 billion annual budget. And the agency's immigration raids have become politically and emotionally charged, as federal agents dressed in riot-like gear have swept into businesses and rounded up hundreds of illegal workers.