FORMER U.S. President Donald Trump must testify under oath in the New York Attorney General’s civil investigation into his business practices, an intermediate state appeals court ruled on Thursday.

A four-judge panel unanimously upheld a trial court decision from February enforcing subpoenas for Trump and his two eldest children, Donald Trump Jr. and Ivanka Trump, to provide deposition testimony in Attorney General Letitia James’ investigation.

"Once again, the courts have ruled that Donald Trump must comply with our lawful investigation into his financial dealings," James said in a statement. "We will continue to follow the facts of this case and ensure that no one can evade the law."

Alan Futerfas, a lawyer for Trump, did not immediately respond to a request for comment.

In January, James said her nearly three-year investigation into the Trump Organisation had uncovered significant evidence of possible fraud.

She described what she called misleading statements about the values of the Trump brand and six properties, saying the company may have inflated real estate values to obtain bank loans and reduced them to lower tax bills.

Trump issued a statement earlier this year calling the accusations false and accusing James of a political agenda in targeting him and his family.

Trump and his children have said testifying would violate their constitutional rights because their words could be used in a related criminal probe led by Manhattan District Attorney Alvin Bragg, which James joined last May.

Trump, a Republican, has also accused James of selectively prosecuting him because he is a political enemy. James and Bragg are Democrats.

The appeals court rejected those arguments, saying James reviewed "significant volumes of evidence" before issuing the subpoenas.

"Appellants have not identified any similarly implicated corporation that was not investigated or any executives of such a corporation who were not deposed," the court said of the Trumps. "Therefore, appellants have failed to demonstrate that they were treated differently from any similarly situated persons."