Protests erupted outside of Gracie Mansion after Mayor Bill de Blasio imposed a vaccine mandate for city workers.

The rally comes ahead of Friday's deadline for the city workforce to receive at least one shot of the COVID-19 vaccine by 5 p.m. or be placed on unpaid leave until they receive the vaccine.

Unions representing firefighters in the city gathered for a press conference Wednesday, saying the mandate is not only insulting to the men and women of the FDNY, but will also lead to a major shortage of first responders.

Hundreds of protesters gathered outside of they mayor's home saying they don't want the vaccine and they want to continue working. They also say that many of them have natural immunity because of how many people within their work force has contracted COVID.

The FDNY says that 68% of its members are currently vaccinated. Union members say that means 35,000 members are yet to be vaccinated and are fearing major shortages come Monday.

Sources say there is a potential that 20% of fire companies will be closed, and there will be 20% less ambulances on the road.

But the mayor says says this won't be a concern come Monday. Officials have been working to prepare - mandatory overtime, scheduling changes, as well as pulling people from stationary positions to get in ambulances and fire trucks.

Fire Commissioner Daniel A. Nigro says the FDNY will implement mandatory overtime to fill any potential staffing shortages, cancel vacations, return uniformed members in offline positions to the field, and have EMS enact mutual aid from volunteer units and private hospitals.

FDNY-Firefighters Association President Andrew Ansbro says lives will be lost if the city faces a first responder shortage.

"There's fires every day, but there's on average 90 to 100 heart attacks a day," he says. "If those response times climb to 15 minutes, 20 minutes, which is most likely going to happen, a lot of cases, that is a death sentence to someone with a heart attack. I'm assuming that the commissioner is telling the mayor, we got this, I'm telling you, you're wrong."

Mayor Bill de Blasio said during his Wednesday press conference that he expects a surge of city workers to get the vaccine shot on Friday, comparing it to the surge of health care workers and Department of Education workers getting their shots ahead of their respective vaccination deadlines.

"We had this pattern with everyone who works for the Department of Education, which is, by far, our biggest agency - a surge of vaccination right up to the deadline," he says. "And then, some people who didn't get vaccinated by the deadline, but recognize that they're about to be put on unpaid leave, who would then go out and get vaccinated immediately, and then even others who get vaccinated in the days after."

When the mayor was asked about a contingency plan for a potential shortage of first responders, the mayor says the focus will be on shifting assignments to where there is a particular need.

The mayor says there will be resources to account for potential NYPD staffing shortages, including offering overtime and making other adjustments as necessary, and that every agency commissioner is confident they can make the adjustments necessary.

The NYPD's current vaccination rate is 73%, according to the agency.

Police Benevolent Association President Patrick Lynch spoke out Wednesday after a New York state supreme court judge denied the police union's request for a temporary restraining order to halt the implementation of the vaccine mandate while its lawsuit to have the mandate declared illegal moves forward.

"The haphazard rollout of this mandate has created chaos in the NYPD. City Hall has given no reason that a vaccine mandate with a weekly testing option is no longer enough to protect police officers and the public," Lynch says. "Instead, police officers are being told to make a possibly life-changing decision in a matter of days to meet a completely arbitrary deadline, while the NYPD's leadership spins its wheels and offers no guidance."

The Department of Correction says 51% of staff have received at least one dose of the vaccine as of Oct. 20.

For the DOC, which has been struggling with attendance and has been on the receiving end of criticism about the conditions of city jails as Rikers recently saw its 13th inmate die this year, is strongly pushing staff to get vaccinated.

Non-uniformed DOC staff and uniformed staff assigned to medical positions must be vaccinated by Friday or be assigned to a non-medical post, while the deadline for uniform employees is later this year to attempt to ease the burden in jails, according to the agency.

Uniform officers have until Dec. 1 to provide proof of vaccination, or be placed on unpaid leave until proving they have received a shot.

Union members including Ansbro say the issue can be fixed if the city puts a testing option back in place, which the mayor has said will not happen.