Mayor Michael Bloomberg says he’s in favor of putting people’s fingerprints on Social Security cards.

Bloomberg says such biometric identification cards would make it easier for employers to judge whether someone has legal permission to work in the U.S.

He says it would reduce the supply of work to illegal immigrants, leading fewer to enter the country.

Critics have said that such a system would raise cost and privacy concerns.

Bloomberg was one of several politicians who discussed immigration issues this week with President Barack Obama.

Bloomberg’s immigration reform group, the Partnership for a New American Economy, supports bringing more immigrant workers and entrepreneurs into the country.

The mayor, who’s also a billionaire businessman, spoke Friday on WOR radio.