Homeland Security Secretary Janet Napolitano is heading to Congress to discuss immigration.

Napolitano, who is to appear Thursday before the House Judiciary Committee, is testifying for the first time since the Obama administration announced plans to stop deporting many illegal immigrants brought to the United States as children who don't have a criminal record. The policy change, which could affect more than a million illegal immigrants, allows eligible people to stay in the country and apply for work permits.

House Republicans have widely criticized the plan, calling it "backdoor amnesty" that circumvents the will of Congress.

Judiciary Committee Chairman Lamar Smith, a Texas Republican, has been among the harshest critics of the administration's immigration enforcement policies.