De Blasio's pledge to reform police practices helped sweep him into office last year. And in recent weeks he's pushed for the right of demonstrators to gather to protest the killings of Michael Brown and Eric Garner, two unarmed African-American men, at the hands of white police officers.
But critics -- including those in the police force -- are accusing him of fomenting an anti-police fervor that contributed to the killings of officers Wenjian Liu and Rafael Ramos.
On Monday, de Blasio tried to reduce tension in the city.
"We have to get everyone to move away from anger and hatred," he said during an afternoon press conference. "If there are differences, we have to address them peacefully. We have to give people faith that their concerns can be heard peacefully across the spectrum and we have to move forward."
He said New York will not "be the kind of city it was meant to be if there is a division between our police and the community."
"The police are our protectors and they must be respected as such," he added.
He said the murders this weekend were "an attack on all of us" during luncheon remarks at the Police Athletic League shortly before his afternoon press conference. And the mayor also called for a hiatus from the protests that have gripped the city and the nation, saying the should focus instead on Liu and Ramos' families.
"It's time for everyone to put aside political debates, put aside protests, put aside all of the things that we will talk about in due time," he said. "Let's accompany these families on their difficult journey. Let's see them through the funerals ... then the debate can begin again."
But during his afternoon press conference, he also pushed back against his critics, calling remarks from the head of the city's police union "wrong and mistaken."
De Blasio also accused the media of contributing to the atmosphere of tension between police and protesters.
"What are you guys gonna do — are you going to keep dividing us?" a visibly angry de Blasio asked reporters, asserting that the media had unfairly focused on a few examples of violence that did not reflect the majority of protesters.
"You all are part of this, too," he added.
President Barack Obama and Attorney General Eric Holder have spoken out on the killings of Brown and Garner, calling for Americans to open up a dialogue on race and law enforcement and sharing their own experiences with racism. Obama has launched a task force to examine cases where there may be uneven applications of the law and propose fixes.
But a startling divide between how white Americans and minorities view the criminal justice system, revealed by a new CNN/ORC poll, underscores the challenge facing both de Blasio and Obama as they struggle to find a solution to broken relationship between the police and the communities they serve.
The nationwide poll, conducted largely before Liu and Ramos were shot and released Monday, shows 57 percent of white Americans think none or almost none of the police in their area are prejudiced against blacks.
Just a quarter of non-white Americans feel the same.
And while 50 percent of white Americans say the criminal justice system treats blacks fairly, only 21 percent of non-white Americans agree.
The shooting this weekend prompted police departments from Colorado to Washington, DC, to warn their officers to remain vigilant and watch out for potential copycat violence against them.
Former New York City Mayor Rudy Giuliani said this weekend on CNN that de Blasio had sparked "intense, anti-police hatred" with his support for protesters. Patrick Lynch, the head of NYPD's police union, also lashed out at de Blasio, saying that there's blood on the hands of those who have supported the protesters and it "starts on the steps of city hall in the office of the mayor."
While de Blasio tried to downplay the politics of the situation during a press conference this weekend, Giuliani and others — largely Republicans — have argued his policies are directly to blame.
"It is the right time to talk about [de Blasio's] policies. His policies of allowing protests to get out of control, and of his not emphasizing enough the importance of fatherhood, the importance of education, the importance of an alternative to a public education system that is failing the black children," Giuliani, a Republican, said on Fox News this weekend.
Giuliani also placed the blame on "propaganda" from the President.
"We've had four months of propaganda starting with the President, that everybody should hate the police. I don't care how you want to describe it, that's what those protests are all about," Giuliani said.
Others took aim at Holder.
"Sickened by these barbaric acts, which sadly are a predictable outcome of divisive anti-cop rhetoric of #ericholder & #mayordeblasio," tweeted former New York Gov. George Pataki, a Republican.
Still, tensions between the police and the city's mayors are nothing new, and indeed haven't yet reached the breaking point they saw under former Mayor David Dinkins, who oversaw — and was unable to control — an all-out riot by police in 1992.
Then, much of the criticism from police was the same: "He never supports us on anything," an officer quoted by the New York Times said at the time.
New York City Police Commissioner Bill Bratton said Monday, however, that his first 10 years in the police force, in 1970, "were around this type of tension."
Bratton cautioned against politicizing the tragedy, but agreed that the shooting of the two officers this weekend "was a direct spinoff" of the recent protests, and that de Blasio has work to do in rebuilding support within the police community.
