New York City Mayor Bill de Blasio has urged his city to heal and support the families of two slain officers.
"Our first obligation is to respect these families," Mr de Blasio said, asking the city "put aside" debate and protests in the coming days.
He has been accused of stoking tensions between police and minorities after two officers were shot dead on Saturday.
The fatal shooting came after weeks of protests following the killing of an unarmed black man by New York police.
Eric Garner died after being placed in an chokehold by police in the summer. He was one of several black men or young boys killed by police in 2014.
'Hold the debate'
Speaking to a police athletic charity luncheon on Monday, Mr de Blasio said the attack on two police officers was "an attack on all of us".
He said the families of Wenjian Liu, 32, and Rafael Ramos, 40, had suffered "unspeakable pain" and the city must show "we will stand by them".
Mr de Blasio called on all organisations to not hold protests or make political statements until the officers were laid to rest.
"Let's see them through the funerals," he said. "Then debate can begin again".
Earlier, Police Commissioner Bill Bratton told NBC he strongly rejected the notion the mayor had increased the risk to police officers by appearing to side with protesters following the death of Garner.
"There are a lot of moving currents creating tension and atmosphere," he said, referring to unpopular pension changes.
He was also critical of the officers who turned their back on Mr de Blasio as he entered a news conference about the shooting of two police officers.
Ismaaiyl Brinsley, 28, shot and killed Liu and Ramos as they were sitting in a patrol vehicle in the borough of Brooklyn.
After firing four bullets through the front passenger window, he fled to a nearby subway station, where police said he shot himself in the head.
Brinsley had a history of violence and mental instability and had been arrested at least 19 times in Georgia and Ohio, police said.
After the death of Garner in New York, Mr de Blasio had talked about his fears for his mixed race son - comments now being seized on by his critics.
The head of the New York City police union said the mayor had "blood on his hands" and former New York governor George Pataki described the shootings as "a predictable outcome of divisive anti-cop rhetoric" from the mayor.
Former New York Mayor Rudy Giuliani said while he disagreed with some of Mr de Blasio's policies he did not think the mayor "is responsible for this".
"I think that's an incorrect and incendiary charge," he told broadcaster CBS.
When Brinsley arrived in New York on Saturday, hours after wounding an ex-girlfriend, Shaneka Thompson, in Baltimore, he threatened on Instagram to kill police officers.
He mentioned Gardner and Michael Brown, another unarmed black man who died in the summer at the hands of the police.
New York's chief of detectives Robert Boyce said Brinsley had also shared his feelings of "self-despair and anger at himself and where his life was" in recent posts.
Police departments in New York and several other cities were said to be operating on "high alert", fearful of copy-cat attacks.
The NYPD has suspended all auxiliary patrols for the time being, and police unions have told officers to respond to every radio call with two cars and to not make arrests "unless absolutely necessary".
Officials are also expecting protests in Milwaukee, Wisconsin, after prosecutors said they would not charge a police officer who shot a mentally-ill black man at least 14 times after they traded blows following the police officer's attempt to search him.
Meanwhile, the family of officer Ramos joined community leaders near their home in Brooklyn for a prayer vigil on Sunday and a makeshift memorial has sprung up at the site of the shooting.
What happened in Milwaukee?
- Officer Christopher Manney shot Dontre Hamilton 14 times
- Milwaukee County District Attorney's Office announced on Monday he will not be charged
- The incident happened in April after workers at a Starbucks called police to complain about Hamilton sleeping in a park
- His death sparked a series of protests in Milwaukee