Donald Trump and his adult children were sued for "numerous acts of fraud and misrepresentation" on Wednesday by New York state's attorney general in a civil investigation into the former U.S. president's business practices, court records showed.

The lawsuit, filed in a New York state court in Manhattan, accused the Trump Organization of engaging in "numerous acts of fraud and misrepresentation" in preparing Trump's annual statements of financial condition from 2011 to 2021. It also named the Trump Organization, the former president's son Donald Trump Jr. and his daughter Ivanka Trump as defendants.

Attorney General Letitia James said Trump and the Trump Organization misstated the values of its real estate properties to obtain favorable loans and tax benefits. She said she was referring allegations of criminal wrongdoing to federal prosecutors in Manhattan and the Internal Revenue Service.

"With the help of his children and senior executives at the Trump Organization, Donald Trump falsely inflated his net worth by billions of dollars to unjustly enrich himself and cheat the system," James said in a statement.

Trump has denied any wrongdoing and described James' probe as "a politically motivated witch hunt." James is a Democrat. The Trump Organization has called James' allegations "baseless." 

Wednesday's lawsuit followed a contentious investigation in which James accused Trump, his company and some family members of using delay tactics to ignore subpoenas and avoid testifying.

Trump on August 10 declined to answer questions in a lengthy, closed-door deposition at the office of the attorney general, invoking his constitutional right against self-incrimination more than 400 times.

Donald Trump Jr. and Ivanka Trump agreed to sit for depositions only after court decisions required it. 

Another of Trump's children, Eric Trump, invoked the right against self-incrimination more than 500 times in a 2020 deposition.

The lawsuit marks one of the biggest legal blows for Trump since he left office in January 2021. 

The FBI conducted a court-approved search of Trump's Mar-a-Lago estate in Florida on August 8 as part of a criminal investigation into his handling of presidential records including classified material.

(With input from Reuters)