New York Police officers Sunday ignored Commissioner Bill Bratton's request and turned their backs on Mayor Bill de Blasio for the third time in as many weeks. Bratton had asked officers to refrain from airing grievances at the funeral of Wenjian Liu, 32, one of two officers slain Dec. 20 as they sat in their squad car in Brooklyn eating lunch. Officer Rafael Ramos, 40, was buried last week.

"As we start a new year, a year we're entering with hearts that are doubly heavy" from the deaths of Liu and Ramos, WABC-TV, New York, quoted de Blasio as saying. "Let us rededicate ourselves to those great New York traditions of mutual understanding and living in harmony. Let us move forward by strengthening the bonds that unite us, and let us work together to attain peace."

Several thousand police officers, watching the Buddhist funeral outside on video screens, turned their backs as de Blasio spoke, despite a memo Bratton issued Saturday in which he said "a hero's funeral is about grieving, not grievance," WCBS-TV, New York, reported.

"All of our city is heartbroken today," de Blasio said in his eulogy, WNBC-TV reported. "All of the city is feeling the pain right now. All of this city wants to lift up the Liu family and the Ramos family."

Reuters reported tens of thousand of police officers had been expected to attend.

"When one of us loses our lives, we have to come together," Officer Lucas Grant of the Richmond County Sheriff's Office in Augusta, Georgia, told WNBC.

The gunman who killed Liu and Ramos, Ismaiiyl Brinsley, killed himself shortly afterward in a nearby subway station. He had posted on social media that the killings were in retaliation for the deaths of unarmed black men Michael Brown of Ferguson, Missouri, and Eric Garner of Staten Island, New York, during the summer.

Officers were incensed by remarks de Blasio made supporting protesters who demonstrated against the Brown and Garner shootings. They were also angered by de Blasio's comment about talking to his bi-racial son, Dante, about how to handle himself with police.

Patrick Lynch, who heads the city's largest police union, accused de Blasio of having blood on his hands after Ramos and Liu were killed.