(AP) - Michael Bloomberg on Sunday apologized for his longstanding support of the controversial “stop-and-frisk” police strategy ahead of a potential Democratic presidential run, a practice that he embraced as New York’s mayor and continued to defend despite its disproportionate impact on people of color.

Addressing a black church in Brooklyn, Bloomberg said he was “sorry” and acknowledged it often led to the detention of blacks and Latinos.

“I can’t change history,” Bloomberg told the congregation. “However today, I want you to know that I realize back then I was wrong.”

Bloomberg’s reversal is notable for someone who is often reluctant to admit wrongdoing. It’s also a recognition that if he’s to compete for the Democratic presidential nomination, he’ll have to win support from black voters. And his record on stop-and-frisk is a glaring vulnerability that could hobble his potential candidacy if he doesn’t express contrition.

The apology, however, was received skeptically by many prominent activists who noted that it was made as he is taking steps to enter the race.

“It is convenient that Bloomberg suddenly apologizes but has done nothing to undo the immense damage he has caused on countless lives,” said activist DeRay Mckesson. “His apology is not accepted.”

Stop-and-frisk gave police wide authority to detain people they suspected of committing a crime, and Bloomberg aggressively pursued the tactic when he first took over as mayor in 2002. Under the program, New York City police officers made it a routine practice to stop and search multitudes of mostly black and Hispanic men to see if they were carrying weapons.

Police claimed that people were only targeted if officers had a reasonable suspicion that they were breaking the law. But while the searches did lead to weapons being confiscated, the overwhelming majority of people who were detained and frisked were let go because they hadn’t done anything wrong.

Many men found the encounters humiliating and degrading, and statistics showed that minorities were far more likely to be subjected to such a search.

“Under Bloomberg, NYPD increased stop and frisk from 100,000 stops to nearly 700,000 stops per year. 90% of those impacted were people of color - overwhelmingly black and brown men,” black activist and data scientist Samuel Sinyangwe tweeted on Sunday. “Bloomberg personally has the money to begin paying reparations for this harm. ‘Sorry’ isn’t enough.”

Bloomberg is not the first Democrat aiming to unseat President Donald Trump next year who has sought to atone for past positions on matters that deeply impacted people of color.