A US congresswoman has been indicted on federal charges, alleging she assaulted and interfered with immigration officers in a skirmish outside a New Jersey detention centre.

Acting US Attorney for New Jersey Alina Habba announced the grand jury indictment of Democrat LaMonica McIver in a post on X.

“While people are free to express their views for or against particular policies, they must not do so in a manner that endangers law enforcement and the communities those officers serve,” Habba said.

McIver said the charges amounted to the Trump administration trying to scare her.

“The facts of this case will prove I was simply doing my job and will expose these proceedings for what they are: A brazen attempt at political intimidation,” she said.

McIver was charged in a complaint by Habba last month with two assault charges stemming from the May 9 visit to Newark’s Delaney Hall — a 1000-bed, privately owned facility that the US’s Immigration and Customs Enforcement uses as a detention centre.

The indictment includes three counts of assaulting, resisting, impeding and interfering with federal officials.

Habba said two of the counts carried a maximum sentence of up to eight years in prison. A third had a maximum sentence of one year.

McIver’s lawyer, former US Attorney for New Jersey Paul Fishman, said that they would challenge the allegations “head-on” in court.

“The legal process will expose this prosecution for what it truly is – political retaliation against a dedicated public servant who refuses to shy away from her oversight responsibilities,” Fishman said.

The indictment is the latest development in a legal-political drama in which President Donald Trump’s administration has taken Democratic officials from New Jersey’s largest city to court, tapping into his immigration crackdown and Democrats’ efforts to respond.

The prosecution of McIver is a rare federal criminal case against a sitting member of Congress for allegations other than fraud or corruption.

At the same visit that resulted in McIver’s charges, Newark Mayor Ras Baraka was arrested on a trespassing charge, which was later dropped. Baraka is suing Habba over what he said was a malicious prosecution.

-AAP