Mass monkeypox vaccination sites opened Sunday at three city schools.

Vaccines could be obtained by appointment-only.

On Sunday, 4,176 doses were available at the three pop-up sites, according to the city's Department of Health.

Officials say the federal government has allocated another 33,000 vaccines to the state. In the coming days, the city should know how many of those doses are coming to the five boroughs. But the commissioner on Sunday said the city will need tens of thousands more to slow the spread.

The vaccines were available at three mass vaccination sites: Aviation High School in Queens, Bushwick Education in Brooklyn and Bronx High School of Science.

The appointments were limited to "gay, bisexual, or other men who have had sex with men and transgender, gender non-conforming, or gender non-binary persons ages 18 and older who have had multiple or anonymous sex partners in the last 14 days," due to limited vaccine supply, the city's Department of Health and Mental Hygiene said in a press release Thursday.

"We've reserved a portion for community partners who can make direct referrals into appointments," New York City's health commissioner Dr. Ashwin Vasan said during a press conference Sunday. "These are community partners that take care of men who have sex with men, people with HIV, people who are in the highest risk groups, and already have long-term trusted relationships with those folks."

The city has had many issues with its monkeypox vaccine rollout. The health department apologized for a website "glitch" last week that made appointments available "prematurely" — an error City Hall blamed on the company running the online vaccine portal.