The number of deaths tied to New York City’s ongoing stretch of extreme cold has risen to 13, according to the mayor’s office — three more than just days ago.

The storm, cold and rising death toll have quickly become the first major test of Mayor Zohran Mamdani’s month-old administration and come during what city officials say could be a record -breaking stretch of dangerous cold.

"Our administration has intensified homeless outreach efforts and successfully made over 800 placements since the beginning of what could be the longest period of consecutive sub-32 degree days in city history,” said mayoral spokesperson Dora Pekec in a statement Friday night.

Advocates and public health experts have long warned that sustained cold poses particular dangers for people living outdoors, especially those with underlying health conditions or substance use disorders.

The mayor spoke about the difficulties of homeless outreach efforts during a press conference Friday, saying officials are limited when it comes to direct intervention like involuntary confinement unless they think a person might represent a harm to themselves or others. He said in situations like this week’s extreme cold, even insufficient clothing can meet that bar.

Involuntary confinement is a “a last resort," Mamdani said, but added, "it has been utilized when city workers have come to that conclusion.”

City workers, he said, were “continuing to canvass people again and again and again … you will inevitably hear a story of someone that they went to who said ‘no’ to them one day, ‘no’ to them the next day, and then, for whatever reason, said ‘yes’ to them the day after that.”

The city’s efforts have included workers from the Department of Social Services and the NYPD conducting expanded sweeps across the city, according to the mayor's office.

As part of what the administration has been calling its “whole of government response,” the city also opened a new low-barrier shelter Friday night, meaning restrictions on drug and alcohol intoxication may be relaxed. Officials said they're also deploying on-call ambulettes to travel through neighborhoods, offering people living outdoors access to warm spaces, meals and medical care.

Deaths linked to cold exposure are tracked across multiple city agencies and final tallies often lag behind real-time events. The most recent annual figures available from the New York City Health Department show that 29 people died from “exposure to excessive natural cold” through all of 2023.

Details are still emerging about those who have died this year, but reporting indicates several have had mental health and substance use issues and have relied on city services in recent years.

One victim struggled with substance abuse, another had been let go from a city-run hospital and a third was a woman who had dementia and walked out into the cold. Another victim was a formerly homeless man who appeared to have found permanent housing for nearly a decade.

Many of the victims remain unidentified.

City officials continue to urge New Yorkers to call 311 if they see someone sleeping outside during freezing conditions, so outreach teams can attempt to bring them indoors.

This is a developing story and has been updated.