NEW YORK (AP) — Thousands of police turned their backs Sunday as Mayor Bill de Blasio eulogized an officer shot dead with his partner, repeating a stinging display of scorn for the mayor despite entreaties to put anger aside.

The show of disrespect came outside the funeral home where Officer Wenjian Liu was remembered as an incarnation of the American dream: a man who had emigrated from China at age 12 and devoted himself to helping others in his adopted country. The gesture among officers watching the mayor’s speech on a screen added to tensions between the mayor and rank-and-file police even as he sought to quiet them.

“Let us move forward by strengthening the bonds that unite us, and let us work together to attain peace,” de Blasio said at the funeral.

Liu, 32, had served as a policeman for seven years and was married just two months when he was killed with his partner, Officer Rafael Ramos, on Dec. 20. Liu’s longtime aspiration to become a police officer deepened after the Sept. 11 terror attacks, his father, Wei Tang Liu, said through tears.

And as he finished his daily work, the only child would call to say: “I’m coming home today. You can stop worrying now,” the father recalled during a service that blended police tradition with references to Buddha’s teachings.

Dignitaries including FBI Director James Comey and members of Congress joined police officers from around the country in a throng of over 10,000 mourners.

“When one of us loses our lives, we have to come together,” said Officer Lucas Grant of the Richmond County Sheriff’s Office in Augusta, Georgia.

After hundreds of officers turned their backs to a screen where de Blasio’s remarks played during Ramos’ funeral last week, Police Commissioner William Bratton sent a memo urging respect, declaring “a hero’s funeral is about grieving, not grievance.”

But some officers and police retirees said they still felt compelled to spurn the mayor. Police union leaders have said he contributed to an environment that allowed the officers’ slayings by supporting protests following the police killings of Eric Garner on Staten Island and Michael Brown in Ferguson, Missouri.

“The mayor has no respect for us. Why should we have respect for him?” said retired New York Police Department Detective Camille Sanfilippo, who was among those who turned their backs Sunday. Retired NYPD Sgt. Laurie Carson called the action “our only way to show our displeasure with the mayor.”

Officers spun back around when Bratton took the podium to speak. Later, de Blasio stood outside the funeral home, to no visible reaction from officers, observing an honor guard and other rituals.

At Liu’s wake Saturday, Gov. Andrew Cuomo called the officers’ slayings a tragic story of “pure and random hatred.” Cuomo didn’t attend the funeral, which came as he prepared to bury his father, former Gov. Mario Cuomo.

The officers’ killer, Ismaaiyl Brinsley, committed suicide shortly after the brazen daytime ambush on a Brooklyn street. Investigators say Brinsley was an emotionally disturbed loner who had made references online to the killings this summer of unarmed black men at the hands of white police officers, vowing to put “wings on pigs” in retaliation.

The deaths strained an already tense relationship between city police unions and de Blasio. Patrolmen’s Benevolent Association President Patrick Lynch, whose rank-and-file union is negotiating a contract with the city, turned his back on the mayor at a hospital the day of the killings and said de Blasio had “blood on his hands.”

Many people, including Cardinal Timothy Dolan, have since pressed all parties to tone down the rhetoric. On Saturday, officers standing outside Liu’s wake saluted as the mayor and commissioner entered.

After Sunday’s show of disdain, Lynch said officers “have a right to have our opinion heard, like everyone else that protests out in the city” and noted that officers’ “organic gesture” was outside the service. The mayor got a respectful reception among police officials inside.

The NYPD declined to comment, and de Blasio spokesman Phil Walzak said the mayor was focused on honoring the fallen officers.

But outside, retired NYPD officer John Mangan stood with a sign that read: “God Bless the NYPD. Dump de Blasio.” And Patrick Yoes, a national secretary with the 328,000-member Fraternal Order of Police, praised Lynch’s stance toward the mayor.

“Across this country, we seem to be under attack in the law enforcement profession,” Yoes said. “We are public servants. We are not public enemies.”

George Breedy, a lieutenant with the St. Charles Parish Sheriff’s Department in Louisiana, said he wouldn’t protest de Blasio. “We’re here to pay respect to the officers,” Breedy said.

Liu’s funeral arrangements were delayed so relatives from China could travel to New York, where he married Pei Xia Chen this fall.

“He is my soul mate,” she said. “My hero.”