For several days, crowds have gathered outside the Metropolitan Detention Center in Brooklyn to protest reports of freezing and dark conditions inside the jail after it partially lost power nearly a week ago.

The protesters have included family members who said they haven't been able to visit inmates in days, as well as activists and elected officials. They've chanted "Move them out!" and demanded answers from jail officials accused of "radio silence." Some have remained at the site overnight, shivering and indignant, in solidarity with inmates, they said.

Through it all, one thing remained constant: the relentless sound of inmates banging against the jail windows, some of them waving lights inside pitch-black cells in an attempt to be seen.

"All we hear are the inmates banging on the windows to get our attention," New York City Councilman Justin Brannan said in a video posted to Twitter after he visited the jail Friday. "And when they see that we're here, they bang louder."

For almost a week, many of those inside the jail, which houses more than 1,600 inmates, had no heat, no hot meals, no hot water for showers and no light in their cells, according to The New York Times, which first reported on the conditions.

For security reasons, inmates were placed on lockdown Thursday - coinciding with a polar vortex that brought record low temperatures to several parts of the country. On Wednesday and Thursday, temperatures in New York ranged from lows in the single digits to highs in the teens.

Those with connections to inmates described deteriorating conditions in the jail, with inmates stuck inside dark, freezing cells, getting sick and "frantic," according to The Times.

"They're really, really scared," Rachel Bass, a paralegal at the Brooklyn federal defenders office, told the newspaper Thursday, after she had taken calls from about 15 inmates. "They don't have extra blankets. They don't have access to the commissary to buy an extra sweatshirt."

The Federal Bureau of Prisons, which runs the jail near Brooklyn's Sunset Park neighborhood, has denied that conditions were so dire. In a statement Sunday, officials said inmates had hot water for showers and in their cells' sinks, and they estimated that power would be fully restored by Monday.

However, several lawmakers who toured the jail Saturday said conditions remained unacceptable and accused jail officials of not understanding the urgency of the situation. Others expressed doubt that heat would be restored by Monday after weeks of earlier inaction.

"After visiting MDC again today it is clear the officials there have disregarded the basic human rights of inmates," Rep. Nydia Velazquez, D-N.Y., tweeted Saturday. "This appalling situation needs to be fixed and I will continue pressuring (the Federal Bureau of Prisons) for immediate action."

Velazquez said one prison guard reported needing to wear fleece over a down vest to stay warm overnight. Late Saturday night, New York Mayor Bill de Blasio said the city's emergency management office would be sending blankets, hand warmers and generators to the federal facility "whether they like it or not."

Rep. Jerrold Nadler, D-N.Y., who also toured the jail, tweeted Saturday that it was clear officials "have been callously placing the health & safety of the inmates at this facility at risk." He returned Sunday and reported things had improved.

"Conditions are much better. It's much warmer," Nadler tweeted Sunday. "And the electrical power will be back tomorrow morning. We will remain vigilant to insure (sic) that the health and safety of the inmates and correction officers are taken care of properly."

The updates Sunday did little to stem the anger outside the prison, where protesters once again gathered. New York Assemblywoman Joanne Simon reported that, although prison officials had accepted the blankets from the city the night before, they had not distributed them to inmates.

Other visitors also reported that conditions remained poor.

"Those who . . . were told heat and hot water are on, we can assure you, this is not true," the nonprofit Justice League NYC said Sunday. "We continue to doubt their claims as elected officials and lawyers who have recently been inside the facility have seen the problems for themselves."

The nonprofit Legal Aid Society said it had written to the MDC warden on Jan. 22, demanding that a lack of heat at the jail be addressed amid forecast temperatures that were "dangerous to human life."

"The Bureau of Prisons' response? Radio silence," the nonprofit said Sunday. "Now they claim they have 'submitted a work ticket' to 'schedule' repairs to a dark, freezing, virtually incommunicado prison. Too little, too late."

Tensions outside the jail increased Sunday afternoon as protesters approached the prison entrance and were pepper-sprayed by guards.

In other harrowing scenes, family members shouted through megaphones to try to communicate with inmates.

"I love you!" one prisoner could be heard yelling from a grated window.

Another woman screamed a name at the top of her lungs in an attempt to pass on a message: "Tell him I'm out here and I love him, and I'm not leaving" until the inmates get heat, she said through a microphone. "I've been here for two days, and I'm not leaving!"