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Outrage among advocates and New York officials was growing on Saturday after reports that a Brooklyn federal jail had limited heat and power during a week when temperatures in the city dropped as low as 3 degrees Fahrenheit.

New York City Mayor Bill de Blasio tweeted Saturday night that the city was sending trucks with "hundreds of blankets and hand warmers" to the jail, and generators were being readied for transport. U.S. Sen. Chuck Schumer, D-New York, tweeted "This has to end. Now."

Protesters attend a rally at Metropolitan Detention Center demanding that heat is restored for the inmates in the Brooklyn borough of New York on Feb. 2, 2019. Go Nakamura / Reuters

On Friday, The New York Times reported that Metropolitan Detention Center in Brooklyn's Sunset Park neighborhood had limited power and heat for the more than 1,600 inmates housed there.

The power issues began around Jan. 5, but the heating issues started last week, the Times reported.

The Federal Bureau of Prisons said in a statement Saturday evening that the jail experienced a partial power outage "due to a fire in the switch gear room" and that the west building had limited power but the east building was unaffected. It said a new electrical panel was installed Saturday by an outside contractor.

"The facility is working to restore power as expeditiously as possible," the agency said in a statement, adding that the work is expected to be completed by Monday.

"Inmates have hot water for showers and hot water in the sinks in the cell," the statement read. "Essential personal hygiene items and medical services continue to be provided. New York City Emergency Services is providing blankets to MDC Brooklyn, and inmates will receive additional blankets and clothing today."

I am outside of the Metropolitan Detention Center where prisoners are without heat. The banging noise is them protesting for all of us to hear. They are without heat for days. This is in BROOKLYN. pic.twitter.com/h3UiVcR6VF — Shahana Hanif (@HShahana) February 1, 2019

Earlier Saturday, the prisons bureau said "Con Edison has been dealing with numerous power emergencies in the community" and that "MDC Brooklyn is working with Con Edison to resolve the issue as soon as possible."

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However, Con Edison said they were not having power issues on their end and any electrical issues at the jail were internal and the jail's responsibility to fix.

The Metropolitan Detention Center (MDC) is shown Jan. 8, 2017, in the Brooklyn borough of New York. Kathy Willens / AP file

In response to reports of extremely cold conditions, Donna Lieberman, executive director of the New York Civil Liberties Union, called on the jail to move inmates to a location where their needs would be met and to fix the issues inside the facility immediately.

"It is shocking that the government would hold people for days on end in a dark, freezing jail during one of the coldest weeks in memory," Lieberman said in a statement. "People incarcerated at the Metropolitan Detention Center (MDC) deserve to be treated with dignity and respect, not forced to struggle to survive in dangerously freezing temperatures."

Now, outside MDC Brooklyn pic.twitter.com/zvXISDHomg — Gideon Orion Oliver (@gideonoliver) February 2, 2019

On Friday, New York City Council Speaker Corey Johnson tweeted that he and fellow politicians New York Rep. Nydia Velázquez, Assemblywoman Jo Anne Simon, Councilmen Brad Lander, Carlos Menchaca, Justin Brannan — all of whom represent parts of Brooklyn — were at the jail to see the situation for themselves, according to a tweet from Johnson.

On Saturday, Lander tweeted that he and other politicians would be protesting with other demonstrators outside the jail.

"#SunsetParkGulag must end today," he wrote.

Inmate telephones and computers and televisions had no power, but inmates’ public defender phones and staff phones were working, the prisons bureau said. All areas of the jail have lights, it said.

As reports of the heat and power issues began to circulate, local activists, politicians and officials shared their indignation on Twitter.

New York Sen. Kirsten Gillibrand retweeted a video taken outside the jail, in which it seemed that inmates could be heard banging on the walls on the facility in protest.

"This is inhumane and a violation of the detainees’ constitutional rights. The Bureau of Prisons needs to fix this immediately," Gillibrand wrote.

Mayor de Blasio tweeted on Saturday afternoon that he was sending city agencies to the jail to assess the situation.

"The federal government has massively failed the people being held at the Metropolitan Detention Center," he wrote.

Hours later, de Blasio followed up his initial tweet, writing that the Bureau of Prisons was refusing the city's help "even as their incompetence is on full display for the world."

"The human beings inside the MDC deserve better and they need it NOW," de Blasio wrote.

In the tweet Saturday night, the mayor wrote: "We've told the Federal Bureau of Prisons the supplies are coming — whether they like it or not."

Also on Saturday, New York Attorney Gideon Orion Oliver tweeted a court document that showed U.S. District Judge Analisa Torres had directed the Bureau of Prisons to appear in court on Feb. 5 as part of an evidentiary hearing on Feb. 5 after a defense attorney submitted letters to her office that inmates were being kept in "disturbing living conditions."

Orion Oliver did not immediately return a request for comment made by NBC News about the hearing.