Despite calls from New York's mayor and others for restraint, hundreds of protesters marched through midtown Manhattan Tuesday night, with some holding signs saying "Jail Killer Cops."

The protesters were mostly peaceful as they wound through the city's bustling shopping district.

Mayor Bill de Blasio on Monday called for a pause in protests over police conduct until officers Rafael Ramos and Wenjian Liu are laid to rest.

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Authorities say they were ambushed and killed while sitting in their patrol car in Brooklyn Saturday by Ismaaiyl Brinsley. It was, police say, the final act in a rampage that began when he shot and wounded his ex-girlfriend at her home outside Baltimore, then made threatening posts online, including a vow to put "wings on pigs" and references to high-profile cases of white police officers killing unarmed black men. After shooting the officers, Brinsley ran into a subway station and committed suicide.

The slayings of the two officers have raised concerns and tempers in the already tense nationwide debate surrounding police conduct.

De Blasio faces a widening rift with those in a grieving police force who accuse him of creating a climate of mistrust that contributed to the killings of the officers.

Police Commissioner William Bratton, speaking Tuesday in Rhode Island, said it was "unfortunate" that some protests continued despite the mayor's plea.

Meanwhile, landmarks including the Empire State Building and Rockefeller Center Christmas tree dimmed their lights from 9 p.m. to 9:05 p.m. Tuesday to honor the slain officers.

CBS New York reports protesters marched on Fifth Avenue chanting "How do you spell murderers? NYPD!" and "Indict, convict, send those killer cops to jail. The whole damn system is guilty as hell."

"This is my city and you don't tell me when to stay home. OK. We're canceling Christmas," the station says one protester shouted.

Even though the demonstrations were peaceful, they saw the return of ugly language directed at cops, CBS New York says.

Officers ignored the invective and marched along with stoic faces, black bands on their shields in honor of Liu and Ramos.

WCBS radio reports some passersby spontaneously showed their support for police.

As a group of police officers followed the demonstrators, some people on the street burst into applause for the cops.

One man shook his head at the protesters and said to the police "You don't deserve this."

Earlier in the day, protest organizers spoke in front of flags flying at half-staff with words of sorrow for the slain patrolmen, but they offered a harsh rejection of the mayor's call for a moratorium on protests.

"There's been no moratorium on the police murdering our people!" organizer Travis Morales said.

"You got no right to tell us when, how and whether we can protest," organizer Carl Dix added.

The White House said Tuesday Vice President Biden will attend Ramos' funeral on Saturday. President Obama is vacationing in Hawaii. Funeralplans for Lui haven't been finalized.

De Blasio on Tuesday visited the place where the two officers were killed and led a moment of silence at City Hall in their memory.

De Blasio and first lady Chirlane McCray spent several minutes at the site of Saturday's shooting.

The mayor bowed his head and McCray placed flowers at a memorial for memorial for Liu and Ramos.