More than 100 people have tested positive for COVID-19 in Borough Park and Williamsburg, pointing to a possible cluster of novel coronavirus cases in Brooklyn's ultra-Orthodox neighborhoods, health care workers told Gothamist.

John Lieberman, the CEO of Asisa Urgent Care, confirmed in a statement that the facility, which caters to Brooklyn's Hasidic population, had identified more than 100 infections as of Tuesday.

“We are working on educating the Jewish community in particular to advise them how crucial it is to quarantine themselves, stay away from people, stay home and do not congregate," he said. "We are hopeful the community will continue to understand the importance of this issue.”

The cases were first reported by the Jewish Telegraphic Agency. Asked about the possible cluster during a press briefing on Tuesday afternoon, Mayor Bill de Blasio denied any knowledge of the new development. "If we had a cluster, I assure you, we would tell you," he said. "I asked this very day, we do not have any clusters in New York City."

A spokesperson for the Mayor's Office did not respond to follow-up inquiries on Tuesday evening.

Some health care workers in the ultra-Orthodox neighborhoods said there was fear of setting off a panic in the religious community.

"We didn't want this cluster to happen because it causes hysteria. The overwhelming response can in turn become a collapse of the health care system," said Shlomie Goldberg, a physician's assistant at Chai Urgent Care, which has locations in both Williamsburg and Borough Park. "There are guidelines that we follow — not everyone needs to be tested."

As of Tuesday morning, the city was reporting a total of 814 confirmed cases, with 157 known cases recorded in Brooklyn. This weekend, thousands of tests were conducted at outposts set up by health clinics in Borough Park and Williamsburg, leading to the surge of confirmations on Tuesday, local leaders said.

"We have a lot of positive results now coming back in Williamsburg and Boro Park unfortunately," said Rabbi Abe Friedman, a community leader who helped set up the testing centers. "People can no longer ignore the precautions the state and the city have implemented. We must take this serious."

The condition of those who have tested positive was unclear Wednesday night, but some are currently hospitalized, according to Friedman.

Jewish leaders have voiced concern in recent days about an outbreak within the city's Hasidic neighborhoods, amid growing evidence that many in the community are not taking the coronavirus health crisis seriously. Despite a state restriction on gatherings of 50 or more people, many synagogues across the city continued to hold large weddings on Tuesday. A handful of yeshivas remained open to children as well, local leaders said.

For everyone wondering whether @bariweiss tweet earlier is an overreaction; this is video is a wedding taking place in Williamsburg *RIGHT NOW*



The reason there isn’t any social distancing is because the Ultra Orthodox community is NOT TAKING THIS SERIOUSLY.



PLEASE HELP pic.twitter.com/fDwvmgFbWh — Shulim Leifer (@ShulimLeifer) March 17, 2020

Rabbi Friedman said that the proliferation of positive tests on Tuesday had successfully convinced many in the community to socially isolate. On Tuesday afternoon, members of the Shmira, a private neighborhood crime patrol group, drove through Borough Park and warned residents over a loud speaker to stay indoors. Many have been observing prayers from their porches.

Yosef Rapaport, a 65-year-old Hasidic activist and podcaster, said that Orthodox communities could be "extra vulnerable" to the virus, due to the number of large families living in close proximity, prayer rituals that require being in close contact, and a general distrust of the media. The state's first cluster of coronavirus cases was believed to have spread through a modern Orthodox synagogue in New Rochelle.

Rapaport feared that the delay in widespread understanding of the crisis could mean that many in the community were already exposed.

"We're always a few days late," Rapaport told Gothamist. "It might a huge problem with the intermingling, the prayers, the family events, and the holiday of Purim last week. It’s only manifesting itself right now."