The FBI has arrested a US judge in her courthouse and charged her over allegedly helping an undocumented immigrant evade arrest.

Milwaukee County Circuit judge Hannah Dugan faces two charges for obstruction and concealing the individual from the FBI.

She made an initial appearance in a packed courtroom on Friday (local time) and was released from custody.

The “shocking arrest” comes amid an escalating feud between the Trump administration and US judges over the president’s immigration crackdown.

FBI Director Kash Patel accused Dugan of intentionally misdirecting FBI agents away from a wanted “illegal alien” so he could evade arrest.

“Thankfully our agents chased down the perp on foot and he’s been in custody since, but the judge’s obstruction created increased danger to the public.”

The immigrant in question was Eduardo Flores-Ruiz.

Dugan is accused of escorting Flores-Ruiz and his lawyer out of her courtroom through the jury door last week after learning that immigration authorities were seeking his arrest.

He was chased down by agents outside the courthouse.

The arrest also comes amid a growing battle between the administration and the federal judiciary over the president’s executive actions over deportations and other matters.

US Attorney General Pamela Bondi confirmed that FBI agents had arrested Dugan and stated: “No one is above the law.”

Bondi told Fox News the judge had “put the lives of our law enforcement officers at risk. She put the lives of citizens at risk. A street chase — it’s absurd that that had to happen”.

A statement released to US media on behalf of Dugan said she had “committed herself to the rule of law and the principles of due process for her entire career as a lawyer and a judge”.

“Judge Dugan will defend herself vigorously, and looks forward to being exonerated.”

Democrat Senator Andy Kim said he was tracking the news of the FBI’s “shocking arrest”.

“(FBI Director) Kash Patel has long bragged about using acts of intimidation as FBI Director to appease Donald Trump,” he said.

“This extreme use of federal law enforcement is another example of this intimidation being used to stoke fear in immigrant communities and create chaos in our legal system.”

Democratic Wisconsin Governor Tony Evers accused the Trump administration of repeatedly using “dangerous rhetoric to attack and attempt to undermine our judiciary at every level.”

“I have deep respect for the rule of law, our nation’s judiciary, the importance of judges making decisions impartially without fear or favour, and the efforts of law enforcement to hold people accountable if they commit a crime,” Evers said.

“I will continue to put my faith in our justice system as this situation plays out in the court of law.”

-with AP