New York Mayor Bill de Blasio speaks from the podium to the New York City Police Academy Graduating class in New York Dec. 29, 2014. REUTERS/Carlo Allegri

New York City Mayor Bill de Blasio met privately with some of his toughest critics Tuesday, hoping to bridge a rift with members of the New York Police Department that erupted with the fatal shooting of two officers and citywide protests on police conduct. But police union leaders said after the meeting their gripes remain unresolved, Reuters reported.

“Today’s meeting focused on building a productive dialogue and identifying ways to move forward together. The mayor and police commissioner remain committed to keeping crime in New York City at historically low levels, supporting the brave men and women in uniform who protect us every day, and finding ways to bring police and the community closer together,” mayoral press secretary Phil Walzak said in a statement Tuesday.

Patrick Lynch, president of the Patrolmen’s Benevolent Association, said the meeting brought no resolution, the Associated Press reported. "There were a number of discussions especially about the safety issues that our members face," Lynch said Tuesday in a joint statement from the city's five main police unions read outside the Police Academy in Queens. "There was no resolve. And our thought here today is that actions speak louder than words and time will tell."

Lynch and other police union leaders have candidly criticized de Blasio for encouraging an anti-police atmosphere. De Blasio has said he often warns his biracial teenage son about the “dangers” of police encounters, Reuters said.

Ed Mullins, president of the Sergeants Benevolent Association, also attended the meeting. Mullins has publicly blamed de Blasio for the deaths of NYPD officers Rafael Ramos and Wenjian Liu, who were shot to death in their patrol car Dec. 20 by Ismaaiyl Brinsley. “Mayor de Blasio, the blood of these two officers is clearly on your hands,” the New York Daily News quoted Mullins as saying. “It is your failed policies and actions that enabled this tragedy to occur. I only hope and pray that more of these ambushes and executions do not happen again.”

A crowd of police officers symbolically turned their backs when de Blasio spoke during Ramos’ funeral in Queens Saturday. New York Police Commissioner William Bratton later addressed the tension between the mayor and the police force. “We don’t see each other, the police officers and the people mad at the police,” Bratton said during the service. “If we can learn to see each other, then we will heal, as a department, as a city, as a country. And wouldn’t that be an honor to these officers’ lives.”