Updated

A bill that would block suspected Nazi war criminals from receiving Social Security benefits is heading to President Barack Obama for his signature.

By voice vote late Thursday, the Senate gave final congressional approval to a measure that would shut a loophole that allowed suspected Nazis to be paid millions of dollars in benefits, clearing it for the White House. Under the No Social Security for Nazis Act, benefits would be terminated for Nazi suspects who have lost their American citizenship, a step called denaturalization. U.S. law currently requires a higher threshold -- a final order of deportation -- before Social Security benefits can be stopped.

The legislation was introduced after an Associated Press investigation published in October revealed that Social Security benefits have been paid to dozens of former Nazis after they were forced out of the United States.

The House unanimously approved the bill on Tuesday on a 420-0 vote.

The legislation united Republicans and Democrats, who expressed outrage that U.S. taxpayers were unwittingly financing the retirement of individuals who participated in the Third Reich's atrocities during World War II.

The White House said Friday that it agreed with the thrust of the legislation and is currently reviewing the bill. A Justice Department spokesman, Peter Carr, said the department supports the goal of terminating federal public benefits for individuals found to have participated in the Nazi persecution during World War II. The Social Security Administration did not immediately respond to AP's request for comment on the bill. However, the agency has previously said former Nazis should not be receiving benefits.

AP's investigation found that the Justice Department used a legal loophole to persuade Nazi suspects to leave the U.S. in exchange for Social Security benefits. If they agreed to go voluntarily, or simply fled the country before being deported, they could keep their benefits. The Justice Department denied using Social Security payments as a way to expel former Nazis.

The investigation revealed that the Social Security Administration and State Department voiced strong opposition over the methods used by the Justice Department's Nazi-hunting unit, the Office of Special Investigations.

Two Republican senators -- Chuck Grassley of Iowa and Orrin Hatch of Utah -- have demanded that the Obama administration provide Congress with records explaining how suspected Nazis received the payments and the role the Justice Department played in the program.

Grassley and Hatch cited the AP investigation in letters sent to Attorney General Eric Holder and Carolyn Colvin, the acting commissioner of the Social Security Administration.

In the new Congress that begins next month, Grassley will chair the Senate Judiciary Committee and Hatch will head the Senate Finance Committee.

The Social Security Administration refused the AP's request that it provide the total number of Nazi suspects who received benefits and the dollar amounts. The AP appealed the agency's denial of the information through the Freedom of Information Act.

Grassley and Hatch are seeking broad categories of data -- such as the total number of Nazis who received Social Security benefits and the dollar amount of those payments -- and details about specific cases. For example, they want to know whether a former SS unit commander named Michael Karkoc, whom the AP located last year in Minnesota, would be able to retain his benefits even if removed to another country.