Donald Trump and his two eldest children have been ordered to testify under oath as part of an investigation into alleged fraudulent business practices.

The former US president looks set to appeal the court ruling, which he branded a “continuation of the greatest witch-hunt in history”.

New York judge Arthur Engoron found in favour of state attorney general Letitia James in directing Mr Trump, his son Donald Trump Jr and daughter Ivanka to give evidence within 21 days to her civil inquiry into the family firm.

Judge Engoron said Ms James had “the clear right” to issue her subpoenas and question the Trumps after having uncovered “copious evidence of possible financial fraud”.

Failing to issue subpoenas “would have been a blatant dereliction of duty”, he wrote.

What has each side said about the ruling?

“Today, justice prevailed,” Ms James said in a statement.

“No one will be permitted to stand in the way of the pursuit of justice, no matter how powerful they are. No one is above the law.”

The decision followed a two-hour hearing in which the Trumps’ lawyers accused the Democratic attorney general of flouting their clients’ constitutional rights by seeking testimony she could then use against them in a parallel criminal investigation.

Trump attorney Alina Habba accused James of “selective prosecution and prosecutorial misconduct that this country has never seen”, citing what she called Ms James’s “vile disdain” for Mr Trump, a Republican.

Mr Trump, who has not said whether he will run for president again in 2024, later issued a statement in which he called the accusations false and accused Ms James of a political agenda in targeting him and his family.

“It is a continuation of the greatest witch-hunt in history – and remember, I can’t get a fair hearing in New York because of the hatred of me by judges and the judiciary. It’s not possible!” he said.

Mr Trump could invoke his Fifth Amendment right to remain silent in a deposition – something he has criticised others for doing in the past.

What has the investigation allegedly uncovered?

Last month, Ms James said her nearly three-year investigation into the Trump Organization 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.

The Trumps have not been accused of criminal wrongdoing.

Judge Engoron declined the Trumps’ bid to put Ms James’ request on hold while the criminal case, led by Manhattan district attorney Alvin Bragg, is pending.

That probe resulted last July in tax fraud charges against the Trump Organization and its chief financial officer, Allen Weisselberg. Both pleaded not guilty.

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Dismissing arguments raised by the Trumps’ legal team, Judge Engoron pointed out they could refuse to answer questions.

He noted Mr Trump’s other adult son, Eric, had invoked his constitutional right against self-incrimination more than 500 times when the attorney general’s office questioned him in 2020.

He also rejected claims Ms James’ sometimes aggressive public statements about investigating Mr Trump, including a pledge that “we’re definitely going to sue him”, showed the “impropriety” of her inquiry.

The judge said the trigger for the investigation was not her dislike of the former president, but congressional testimony from Mr Trump’s former personal lawyer Michael Cohen that the Trumps were “cooking the books”.