NYPD Police Commissioner William Bratton and Mayor Bill de Blasio apologized Thursday to James Blake, the retired tennis star who was roughed up and handcuffed by undercover officers outside a Manhattan hotel in a case of mistaken identity.

"I want to make very clear I've reached out to Mr. Blake and I want to talk to him because I want to apologize to him on behalf of the City of New York," de Blasio said on NY1.

Thursday night, Bratton released a statement saying that he had "personally apologized for yesterday's incident. . . . Mr. Blake said he would like to meet with the mayor and me at a future date, which we would be agreeable to."

StoryNYPD: Ex-tennis star mistakenly handcuffedU.S. OpenU.S. Open: Men's results

The talk came amid persistent questions over why Blake, 35, was detained while waiting at the Grand Hyatt in Manhattan for a ride to the U.S. Open.

A police officer who a law enforcement source said is from Nassau County has been placed on modified duty and an independent watchdog group has opened an investigation.

Blake said he was outside the hotel when a man later identified as a police officer charged him and threw him to the ground. The officer did not identify himself as a member of the NYPD at the time, Blake said.

NYPD officials said a confidential witness mistakenly identified Blake during an undercover investigation into cellphone fraud. Blake told reporters Wednesday that "it shouldn't have happened and it's something that we'll deal with the police and we'll find out what they have to say internally."

Earlier Thursday in an interview on CNN, Bratton said that Blake, who is black, had a sriking resemblance to a suspect in the investigation.

"If you look at the photograph of the suspect, it looks like the twin brother of Mr. Blake," Bratton said, adding that "race had nothing to do with this."

advertisement | advertise on newsday

On ABC's "Good Morning America" Thursday, Blake said: "I was standing there doing nothing -- not running, not resisting, in fact, smiling."

The NYPD launched an internal affairs investigation hours after officers detained Blake.

The officer's modified assignment came after investigators viewed surveillance video, the NYPD said. The head of the city's Civilian Complaint Review Board said his agency is also investigating. The law enforcement source identified the undercover detective as James Frascatore, 38.

Frascatore has been with the NYPD for about four years, the source said. An excessive force complaint against Frascatore was dismissed by the CCRB and another case was dismissed when the complainant refuse to cooperate.

Frascatore didn't return a call for comment. Patrick Lynch, head of the Patrolmen's Benevolent Association, questioned taking the officer off the street.

Get the Newsday Now newsletter!

The best of Newsday every day in your inbox.

"Placing this officer on modified duty is premature and unwarranted," Lynch said.

With Gary Dymski, Alison Fox,

Joan Gralla and AP