Four men escaped from a privately run immigration detention center in Newark during a disturbance on Thursday after days of unrest over conditions, according to a law enforcement official in New Jersey, a federal spokeswoman and other detainees’ lawyers.

“Additional law enforcement partners have been brought in to find these escapees,” Tricia McLaughlin, a spokeswoman from the Department of Homeland Security, said Friday in a text message.

The detention center, known as Delaney Hall, went into lockdown after dozens of law enforcement officials responded to reports of a disturbance inside the facility on Thursday evening, according to lawyers who have clients detained inside.

A group of migrants inside the facility seemed to mount a revolt on Thursday following days of unrest over the quality and timeliness of meals, the lawyers and relatives who spoke to the detainees over the phone said in interviews.

“People were hungry and got very angry and started to react and started to rebel against what was going on in the detention center,” said Ellen Whitt, a volunteer who works at DIRE, an emergency immigration hotline. A DIRE staff member received a call about 6 p.m. from one detainee, Ms. Whitt said, and “when we were on the phone with him, we could hear screaming and yelling in the background.”

The detainee said that people were trying to break windows and that, at one point, guards seemed to have abandoned their posts, she said.

A law enforcement official familiar with the details of the escape said that the missing men appeared to have exited the building through an unhinged piece of exterior siding.

Masked officers carrying plastic handcuffs and pepper spray could be seen entering the facility just after 7 p.m., and people standing nearby reported smelling a pungent odor. The commotion drew protesters to the facility’s gates who sought to barricade the entrance of the facility.

On Friday morning, officials at the detention facility told immigration lawyers with clients at Delaney Hall that phone calls and visits had been suspended, said Karla Ostolaza, the managing director of the immigration practice at Bronx Defenders. The lawyers were told they should check back next week.

“We have no idea what is happening with our clients right now,” Ms. Ostolaza said.

Mustafa Cetin, a lawyer who has been representing a Turkish man working toward citizenship, said he got an email from the facility at 7:37 a.m. on Friday notifying him that “all movement,” including meetings with lawyers, had been canceled “until further notice.”

Mr. Cetin’s client had been detained about two weeks ago after a routine court appearance in Newark.

Delaney Hall is run by one of the country’s largest private prison companies, the GEO Group, which has a contract with the Trump administration to hold as many as 1,000 migrants at a time. A spokesman for the GEO Group referred questions to the Immigration and Customs Enforcement agency.

The controversy at Delaney Hall comes as President Trump has escalated his immigration crackdown in recent weeks, especially in nearby New York City. A number of immigrants who have been arrested in immigration courts and ICE offices in the city have been transferred to Delaney Hall, which is a 30-minute drive from ICE offices in Lower Manhattan.

ICE entered into a $1 billion contract with the GEO Group to operate the facility, which began housing detainees last month. Democratic officials in New Jersey have opposed its opening, leading to a lawsuit, protests and a volatile clash outside the facility that led to the arrest of Newark’s mayor and assault charges against Representative LaMonica McIver, a New Jersey Democrat. Ms. McIver, who has maintained her innocence, is scheduled to be arraigned on Monday and has said that she will enter a not-guilty plea.

Late on Thursday, Ms. McIver released a statement accusing the Trump administration of “stonewalling efforts to learn the truth” about the situation inside Delaney Hall.

“I have serious concerns about the reports of abusive circumstances at the facility,” Ms. McIver said.

Relatives with appointments scheduled on Thursday to visit detainees in Unit 4 of the facility said that they had not been permitted inside to visit. Many were still waiting out front when a fire truck and then police vehicles from several agencies, including the Newark Police Department and the Essex County Sheriff Department, pulled up.

“They weren’t letting visitors in,” said Raymond O’Neill, a Newark resident, who has joined regularly with other activists outside the facility, which has become a recurring flashpoint in President Trump’s immigration crackdown.

After the sun set, a K9 unit and agents with the Federal Bureau of Investigation, as well as officers from the Hudson County Sheriff’s Office, began arriving as protesters stood in front of the facility’s gate, as if to block entry or exit by the authorities.

Just before 10 p.m., some members of the crowd dragged plastic construction barricades toward the gate. Soon after, groups of protesters began linking arms, blocking a van and an S.U.V. from exiting through the gate. The vehicles left after the crowd was dispersed by officers who used pepper spray.

In recent days, reports about unsanitary conditions inside began to percolate among immigration lawyers and activists.

Law enforcement pushing back demonstrators protesting immigrant detentions.Credit...Bryan Anselm for The New York Times

Francisco Castillo, a Dominican immigrant who has been held at Delaney Hall since last week, said in a phone interview from the detention center on Tuesday that the facility was so overcrowded when he arrived that some detainees had to sleep on the floor. He said on Tuesday that the crowding issue had been recently resolved.

But he said detainees were being served dismal meals at irregular hours, an issue that was particularly affecting detainees who are diabetic and need to eat at regular times to control their blood sugar levels. He said detainees were often served small cartons of expired milk for breakfast. Dinners were sometimes not served until about 11 p.m., he said.

The living conditions grew so bad, he said, that a group of about 30 detainees had begun drafting a petition detailing the conditions that they could get to the public through their relatives and lawyers.

“Every day is a disaster with the food here,” Mr. Castillo, 36, who was detained by ICE at an immigration courthouse in New York City on June 4, said in Spanish.

About 4:30 p.m. on Thursday, a woman who lives in Elizabeth, N.J., said she got a call from her partner, who has been detained at Delaney Hall since early last month. He was crying, she said, and described rising tension within the facility linked to frustration over food.

He had arrived in the country at 15 from Guatemala, she said, and is challenging an order of deportation.

The woman, who did not want to be identified because she feared it would lead to retaliation against her partner, said she told him to close the door to the 10-bunk dorm room where he is housed and to kneel on the floor to avoid a conflict if officers entered.

Demonstrators assisted a person who was pepper-sprayed while protesting.Credit...Bryan Anselm for The New York Times

Tracey Tully is a reporter for The Times who covers New Jersey, where she has lived for more than 20 years.

Luis Ferré-Sadurní is a Times reporter covering immigration, focused on the influx of migrants arriving in the New York region. (BBC)

•Protesters used barricades to try to impede federal agents at Delaney Hall in Newark on Thursday.Credit...Victor J. Blue for The New York Times