New York Attorney General Letitia James, a longtime foe of President Donald Trump, was indicted on charges of lying on a mortgage application on Thursday, the Justice Department said, as the administration seeks to use government power against those who have pursued investigations into him or publicly resisted his agenda.

A grand jury in Alexandria, Virginia, returned an indictment charging James with one count of bank fraud and one count of making a false statement to a lending institution, court records showed.

James, a Democrat, said in a statement she would continue serving as New York state's top law enforcement official and called the charges "a continuation of the president's desperate weaponisation of our justice system."

"We will fight these baseless charges aggressively," James said.

The indictment accuses James of falsely telling a bank that she would occupy a Norfolk, Virginia, home she bought in 2020 for around US$137,000 as a secondary residence, when she allegedly used it as an investment property.

The indictment said the alleged misrepresentation allowed James to receive a favourable interest rate, saving her around US$19,000 over the life of the loan.

"The charges as alleged in this case represent intentional, criminal acts and tremendous breaches of the public's trust," Lindsey Halligan, the US attorney for the Eastern District of Virginia, said in a statement.

A federal judge scheduled James' initial court appearance for October 24 in Norfolk, Virginia.

Trump, a Republican who campaigned in part on a vow of retribution after facing a slew of legal woes since his first term in the White House ended in 2021, has repeatedly assailed James on social media and at political rallies as a partisan enemy.

"This is what tyranny looks like," Senate Democratic Leader Chuck Schumer, who represents New York, said in a statement.

"President Trump is using the Justice Department as his personal attack dog."

The indictment of James comes after a grand jury in Virginia on September 25 indicted former FBI Director James Comey on charges of making false statements and obstructing a congressional investigation. Comey pleaded not guilty on Wednesday.

Both indictments come after Trump, in a September 20 social media post addressed to US Attorney General Pam Bondi, said James, Comey, and US Senator Adam Schiff were "guilty as hell."

The indictments against James and Comey were both brought by Halligan, who was installed last month as the top federal prosecutor in Alexandria, Virginia.

Her predecessor, Erik Siebert, resigned on September 19, hours after Trump told reporters, "I want him out."

Siebert believed the evidence against Comey and James was weak, two people familiar with the matter told Reuters at the time. (Reuters)