New York City Mayor Bill de Blasio said Wednesday he won't apologize for past remarks that antagonized some police officers, but he pledged to address "valid issues" raised by cops and he harshly criticized the rhetoric of the most extreme anti-NYPD protesters as "sick."

De Blasio's remarks came as Gov. Andrew M. Cuomo met privately at his Manhattan office with police union leaders to try to heal their divisions with de Blasio.

The mayor said he can't take back remarks he made voicing empathy with New Yorkers who were upset when a Staten Island grand jury last month decided not to charge a police officer in the death of Eric Garner.

Union leaders, including Patrolmen's Benevolent Association president Patrick Lynch, were particularly incensed when de Blasio recalled coaching his biracial son, Dante, to be cautious around cops.

"You can't apologize for your fundamental beliefs," de Blasio said at an unrelated news conference in the Bronx.

But other comments by the mayor Wednesday suggested a deliberate shift in tone. Unprompted, he laced into protesters who direct hateful comments at cops, Newsday reports.

Anti-brutality demonstrations are set to resume Thursday after a lull in the aftermath of the Dec. 20 killings of two police officers. The mayor called out sponsoring groups that have "a long history of, unfortunately, allowing some of their members to say really inappropriate, reprehensible things about our police officers -- things that I think are actually quite sick, anything that suggests violence towards police."