Watch What Cops Do as New York City Mayor Bill de Blasio Walks Into Press Conference on Slain NYPD Officers

Police officers appeared to turn their backs on New York City Mayor Bill de Blasio as he walked into a police press conference Saturday on the two NYPD officers fatally shot while sitting in their patrol car in Brooklyn, WPIX-TV reported.

Relations between the mayor's office and the police department have been quite tense.

Police in New York are being criticized for their tactics following the chokehold death of Eric Garner, who was stopped by police on suspicion of selling loose, untaxed cigarettes. Amateur video captured an officer wrapping his arm around Garner’s neck and wrestling him to the ground. Garner was heard gasping, “I can’t breathe” before he loses consciousness and later dies.

Demonstrators around the country have staged die-ins and other protests since a grand jury decided Dec. 3 not to indict the officer in Garner’s death, a decision that closely followed a Missouri grand jury’s refusal to indict a white officer in the fatal shooting of Michael Brown, an unarmed black 18-year-old.

In a press conference about the grand jury non-indictment, de Blasio said he had warned his 17-year-old, mixed-race son, Dante, to be careful around police officers, the New York Post reported.

The president of the police officers union, Patrick Lynch, and de Blasio have been battling publicly over treatment of officers following the grand jury's decision regarding the Garner death. Just days ago, Lynch suggested police officers sign a petition that demanded the mayor not attend their funerals should they die on the job.

Image source: Patrolmen’s Benevolent Association website

At the press conference, de Blasio said the two fallen officers are heroes.

The Associated Press contributed to this story.

This story has been updated.