The former New York mayor backed a tactic that disproportionately targeted black and Latino residents.
Michael Bloomberg, the billionaire former mayor of New York who has made moves towards running as a presidential candidate, has apologised for backing the city's "stop and frisk" policy.
Stop-and-frisk disproportionately targeted black and Latino residents.
Speaking at an African-American church in Brooklyn, New York, Mr Bloomberg said the policy was a mistake.
He believed that stop-and-frisk saved lives, he said, but accepted that good intentions were not good enough.
"I can't change history," he told the congregation at Christian Cultural Centre. "However, today I want you to know that I realise back then, I was wrong, and I'm sorry. But I also want you to know that I am more committed than ever to ending gun violence."
Mr Bloomberg, who was Republican mayor of the city from 2002 until 2013, added that the policy "eroded what we had worked so hard to build: trust".
"Trust between police and communities, trust between you and me," he said. "And the erosion of the trust bothered me, deeply. And it still bothers me. And I want to earn it back."
But the apology was met with scepticism from many, who believe the timing of it betrays a political motive.
Although he hasn't formally announced his candidacy, Mr Bloomberg has indicated that he may join the Democratic race for the presidency ahead of next year's election.
Since the end of his time as mayor, Mr Bloomberg has repeatedly defended the stop-and-frisk policy - including as recently as this January. BBC