New York Mayor Bill de Blasio was so floored Tuesday night by a report of a large funeral gathering in Brooklyn during the coronavirus pandemic that he said he had to see it for himself.

When the Democratic mayor arrived in the Williamsburg neighborhood, he did indeed see hundreds of Orthodox Jewish mourners flooding the sidewalks and intersection of Bedford Avenue and Rutledge Street, honoring the memory of a rabbi who recently died of the novel coronavirus.

The sounds of police sirens blaring through the streets and officers ordering people to go home did little to disperse the crowd, who defied social distancing orders. The mourners, dressed in traditional black garments and hats and forced to yell over the piercing sirens, stood nearly shoulder-to-shoulder, some with, others without masks in a city with almost 158,000 coronavirus cases and nearly 12,000 deaths.

De Blasio was furious. While denouncing the “absolutely unacceptable” large gathering, he said that he had instructed police to institute a “zero tolerance” standard on such gatherings, stressing that people could be subject to arrest as part of the effort to prevent the disease from spreading even more through big groups.

“When I heard, I went there myself to ensure the crowd was dispersed. And what I saw WILL NOT be tolerated so long as we are fighting the Coronavirus,” he tweeted late Tuesday.

He added in a follow-up tweet, “My message to the Jewish community, and all communities, is this simple: the time for warnings has passed. I have instructed the NYPD to proceed immediately to summons or even arrest those who gather in large groups. This is about stopping this disease and saving lives. Period.”

The mayor’s warnings elicited a torrent of criticism. How come, some asked, he had not objected earlier in the day when crowds gathered across the city to watch the military flyover to honor essential workers? Much like the funeral scene in Brooklyn, photos and videos on social media of those watching the Navy’s Blue Angels and the Air Force’s Thunderbirds showed people standing close to each other with many not wearing masks. Critics wondered: Was this not hypocritical?

De Blasio, who was shown watching the flyover in photos and videos and not following his own social distancing orders, was also criticized by local and national leaders for specifically calling out Jewish people when other groups are doing the same thing without the condemning tweets.

“This has to be a joke,” tweeted New York City Councilman Chaim Deutsch, a Brooklyn Democrat who is an Orthodox Jew. He added, “Every neighborhood has people who are being non-compliant. To speak to an entire ethnic group as though we are all flagrantly violating precautions is offensive, it’s stereotyping, and it’s inviting anti-Semitism. I’m truly stunned.”

The councilman chided de Blasio for coming down hard on the funeral crowd just two days after he was seen walking around Brooklyn’s Prospect Park with his wife, Chirlane McCray.

“Has he been to a park lately? (What am I saying — of course he has!)” Deutsch tweeted.

The message was echoed by Jonathan Greenblatt, the CEO of the Anti-Defamation League, who said de Blasio’s sentiment “erodes the very unity our city needs now more than ever.”

“The few who don’t social distance should be called out — but generalizing against the whole population is outrageous especially when so many are scapegoating Jews,” Greenblatt noted.

The New York Police Department and a spokesperson for de Blasio’s office did not return messages late Tuesday. An NYPD spokeswoman told the New York Daily News that no one was arrested or issued a summons for attending the funeral.

The Yeshiva World reported that the funeral was held for Rabbi Chaim Mertz, 73, who recently died of covid-19, the disease caused by the coronavirus. At its peak, there were about 2,500 people at the funeral, which ran from about 7 to 9 p.m. Tuesday, according to the Daily News.

In a video shared by the Williamsburg News, men with the Shomrim, the Orthodox community’s neighborhood watch, are shown instructing their colleagues to let everyone in attendance know that they had to wear a mask.

“Everybody must have a mask,” said one representative with the group. “Most important thing: Everyone should have a mask.”

The images and videos posted to social media, however, indicate that not everyone was wearing a mask during the funeral. Footage captured by WABC showed a stream of mourners parading down Bedford Avenue, many trying to cover their face. At one point, hundreds of people filled the sidewalks and stoops as police attempted to break up the crowd.

The crowded funeral in Williamsburg is the latest of several large Orthodox events that have been broken up because of the pandemic this month.

Earlier this month, police in Brooklyn broke up a funeral for a rabbi in the Borough Park neighborhood, as attendees were ignoring social distancing.

In Lakewood, N.J., police broke up another funeral for a rabbi, this one at a synagogue, and ended up charging 15 men for violating the state’s executive order banning large gatherings. As The Washington Post’s Meagan Flynn reported, police in the New Jersey city have broken up several traditional Orthodox Jewish events because of the large gathering ban, including weddings and bat and bar mitzvahs, and even shuttered a yeshiva that resisted school closure orders.

Conflicts between religious groups of all faiths and public officials trying to enforce coronavirus rules have been a continuing source of stress since the pandemic hit the United States.

New York has been no exception. On Tuesday, de Blasio reiterated that while he empathized with people who want to remember their loved ones, now was not the time for any large gatherings, such as funerals.

“We have lost so many these last two months + I understand the instinct to gather to mourn,” de Blasio tweeted. “But large gatherings will only lead to more deaths + more families in mourning. We will not allow this.”

The chaotic funeral procession got the attention of political consultant Menashe Shapiro, who posted an overhead video of the scene. He wondered what more crowds like this could mean for the city moving forward.

“Scenes like this can set the process of reopening back weeks,” he said. “Worse off, it risks more funerals.”