Washington (CNN) -- The Department of Homeland Security is not helping Alabama as it tries to implement its controversial new immigration law, Secretary Janet Napolitano said Wednesday.
In response to questions from House Judiciary Committee members, Napolitano stressed her department is working with the Department of Justice, which is challenging the law, and it's not clear what the full impact of the measure might be.
Rep. Bobby Scott, D-Virginia, expressed concern about Hispanic citizens. "You would have to assume that Hispanic citizens would be adversely affected, because they would have to be showing ID about everywhere they go," Scott said.
Napolitano replied, "I think that should be a real concern."
The Alabama law -- considered the toughest in the nation -- would require police who make lawful traffic stops or arrests to try to determine the immigration status of anyone they suspect might be in the country illegally. But recently, a federal appeals court at least temporarily blocked some provisions, including one requiring Alabama officials to check the immigration status of children in public schools.
A final ruling on the law is not expected for months.
Rep. Tim Griffin, R-Arkansas, told Napolitano he thinks states like Alabama and Arizona are passing their own stiff immigration laws because the federal government is not securing the nation's borders. He said both this administration and the previous Republican one have failed in that area.
But it is unclear whether border security is getting worse.
The number of arrests of people trying to cross the U.S.-Mexico border illegally decreased 58% from 2006 to 2010, according to statistics from Customs and Border Protection.
In addition, up until 2011, there had been a two-year decline in the unauthorized immigrant population in the United States, according to a Pew Hispanic Center report.
Napolitano also said a lot of information in circulation about border security and cross-border violence is inaccurate. But she added, "In my judgment, I think a number of the states are acting because the Congress has failed to act."
Napolitano said she and others in the Obama administration will continue to work for comprehensive immigration reform.