The mayor of New Jersey's largest city has been released following his arrest on Friday after allegedly trying to force his way into a migrant detention facility.

Newark Mayor Ras Baraka "committed trespass and ignored multiple warnings" to leave Delaney Hall, a facility being run by Immigration and Customs Enforcement (ICE), according to acting US attorney for New Jersey Alina Habba.

Baraka was accompanied by three Democratic members of Congress who were not arrested. They say they were there to conduct "oversight" to ensure the facility was not violating any building safety ordinances.

Baraka told CNN he did not break any laws and was "exercising my right and duty as an elected official".

He has been charged with one count of trespassing.

Ms Habba, who previously worked as a personal lawyer for US President Donald Trump, wrote on X on Friday that Baraka "committed trespass and ignored multiple warnings from Homeland Security Investigations to remove himself from the ICE detention center".

"He has willingly chosen to disregard the law. That will not stand in this state," her statement added.

A separate statement from the Department of Homeland Security (DHS) said that a group of protesters, which included the Democrats, "stormed the gate and broke into the detention facility" as a bus containing illegal migrants was being brought inside the fenced perimeter.

"These members of Congress storming into a detention facility goes beyond bizarre political stunt and puts the safety of our law enforcement agents and the detainees at risk," the statement added.

Baraka told CNN on Friday night that he did not enter the 1,000-bed facility unlawfully. He said he was there for a news conference with the three members of Congress who had been granted entry into the facility.

Videos posted online of the arrest show a chaotic scene as protesters and officers physically clash and Baraka, who is also running to be New Jersey governor, is led away in handcuffs.

Shortly before he is arrested, the footage shows officers telling Baraka he will not be allowed inside. At one point he is told: "That is the last warning. You will be placed under arrest."

New Jersey's Democratic Governor Phil Murphy said he was "outraged" by Baraka's arrest.

Baraka was taken to a DHS detention centre. When he was released after a few hours, he told supporters who had gathering outside the facility: "We didn't do anything wrong."

Earlier this year, Newark filed a lawsuit attempting to block use of the facility, which has become a flashpoint over the Trump administration's deportation policies.

City officials allege the private firm that signed a contract with ICE to operate the facility did not obtain proper permits and blocked necessary inspections. The firm has told media they have the proper permits, while the DHS has said all permits and inspections were up to date.

New Jersey Democratic lawmakers Rob Menendez Jr, Bonnie Watson Coleman and LaMonica McIver were also present during the protest.

Earlier on Friday, Watson Coleman posted on social media: "We're at Delaney Hall, an ICE prison in Newark that opened without permission from the city & in violation of local ordinances.

"We've heard stories of what it's like in other ICE prisons. We're exercising our oversight authority to see for ourselves."

In another post, McIver said that Baraka "did nothing wrong" and had already left the facility when he was arrested.

The move comes as federal agencies continue their crackdown on illegal immigration, following up on a key campaign promise made by Trump. (BBC)

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