Donald Trump looks set to be deposed Wednesday in New York as part of the state attorney general's civil probe into alleged fraud at his family business, the ex-president said on his social media network.

"In New York City tonight," Trump posted on his Truth Social just after midnight.

"Seeing racist N.Y.S. Attorney General tomorrow, for a continuation of the greatest Witch Hunt in U.S. history!" he added. "My great company, and myself, are being attacked from all sides. Banana Republic!"

New York Attorney General Letitia James suspects the Trump Organization fraudulently overstated the value of real estate properties when applying for bank loans, while understating them with the tax authorities in order to pay less in taxes.

Trump and his eldest children, Donald Jr and Ivanka, had been due to start testifying under oath in July but the depositions were postponed due to the death of the former president's first wife.

The Trumps have denied any wrongdoing, and the former Republican leader has charged that the probe is politically motivated.

If James, an African-American Democrat, finds any evidence of financial misconduct, she can sue the Trump Organization for damages but can not file criminal charges, as it is a civil investigation.

James's probe is one of several legal battles in which Trump is embroiled, threatening to complicate any bid for another run for the White House in 2024.

The deposition comes on the heels of a Federal Bureau of Investigation raid on Trump's Florida residence in an escalation of legal probes into the 45th president that has set off a political firestorm.

The FBI declined to provide a reason for the raid, but US media outlets said agents were conducting a court-authorized search related to the potential mishandling of classified documents that had been sent to Mar-a-Lago after Trump left the White House in January 2021.