Donald Trump declined to answer questions under oath on Wednesday in New York state’s civil investigation into his business dealings, pleading the fifth two days after the FBI raided his Florida home in a criminal case, seeking classified documents taken from the White House.

The former US president’s decision to exercise his fifth amendment constitutional right against self-incrimination was delivered during a closed-door deposition in Manhattan, where the New York state attorney general, Letitia James, is examining the Trump family real estate empire.

“I declined to answer the questions under the rights and privileges afforded to every citizen under the United States constitution,” Trump said in a statement as he prepared to appear before James.

Trump’s deposition, which took place in lower Manhattan, appears to have lasted several hours. The former president departed 28 Liberty Street at 3.20pm in a black Secret Service SUV and peered out of the rear window as his motorcade crawled out of an underground garage and drove past onlookers.

After Trump’s deposition concluded, one of Trump’s lawyers, Ronald Fischetti, confirmed that over the course of four hours, including several breaks, the former president had answered just one question – to state his name – and offered a statement calling the inquiry “the greatest witch hunt in the history of country”.

According to the New York Times, Trump accused the attorney general of having “openly campaigned on a policy of destroying me”.

Beyond that, from 9.30am to around 3pm, Trump had repeated the words “same answer” to every question about “valuations and golf clubs and all that stuff”, Fischetti told the Times.

The attorney added that Trump’s decision to take the fifth had been made shortly before the interview started. “He absolutely wanted to testify and it took some very strong persuasion by me and some others to convince him,” Fischetti added.

The high-stakes legal meeting came as pressure from senior Republicans mounted on the US Department of Justice, in the entirely separate case, to reveal details of the federal search at Trump’s Mar-a-Lago residence and private club in exclusive Palm Beach on Monday.

The FBI search, the Guardian has reported, was authorized to seek presidential and classified records that the justice department believes the one-term former Republican president unlawfully retained after his time in the White House was up.

However news of the search triggered outrage from Republican leaders, demanding that Joe Biden’s attorney general, Merrick Garland, swiftly explain the department’s actions.

On Tuesday, Trump’s former vice-president, Mike Pence, expressed “deep concern”, adding on Twitter: “No former president of the United States has ever been subject to a raid of their personal residence in American history.”

Senate minority leader and Kentucky Republican Mitch McConnell called for a “thorough and immediate explanation”.

“Attorney General Garland and the Department of Justice should already have provided answers to the American people and must do so immediately,” McConnell said in a statement.

Meanwhile, the Palm Beach county state attorney, Dave Aronberg, a Democrat, rejected the characterization of the search as a “raid”, telling MSNBC​ that was “a gross exaggeration”.

“This was a very orderly, smooth search of a home conducted by plain clothes FBI agents, escorted by Secret Service agents,​” Aronberg said.​

Trump’s lawyers have a copy of the warrant issued for the search and a list of what the FBI seized, Politico reported.

Back in New York, before Trump’s deposition session on Wednesday, he slammed the legal encounter in a brash post on his Truth Social social media platform, his alternative after he was banned from Twitter.

“In New York City tonight. Seeing racist NYS Attorney General tomorrow, for a continuation of the greatest Witch Hunt in US history!” Trump wrote, repeating an insult he has repeatedly thrown at James, who is Black and the first woman of color ever to hold statewide elected office in New York.

“My great company, and myself, are being attacked from all sides,” Trump also posted, adding: “Banana Republic!”

The case involves allegations that Trump’s company, the Trump Organization, misstated the value of assets including some of his golf courses and skyscrapers, misleading lenders and tax authorities.

At the heart of the case are claims that Trump has for decades falsely inflated his fortune – a dance that involves publicity, maximizing access to bank loans and minimizing tax obligations. “I look better if I’m worth $10bn than if I’m worth $4bn,” he once said. In his book, The Art of the Deal, he chose to describe his business style as “truthful hyperbole”.

In May, James’s office said that the investigation was nearing its conclusion and that investigators had amassed substantial evidence that could support legal action, such as a lawsuit, against Trump, his company or both. The attorney general’s office said Trump’s deposition was one of the few remaining pieces to be collected.

Two of Trump’s adult children, Donald Jr and Ivanka, are believed to have testified in the investigation in recent days. Trump’s testimony was initially scheduled for last month but was delayed after the 14 July death of his ex-wife, Ivana Trump.

Trump has denied the allegations, explaining that seeking the best valuations is a common practice in the real estate industry.

While James has explored suing Trump or his company, the Manhattan district attorney’s office has been pursuing a parallel, criminal, investigation. However, it ran into problems after a new district attorney, Alvin Bragg, raised questions internally about the viability of the case, and its lead prosecutors resigned.

Bragg has said the investigation is continuing.

Commenting further on his refusal to answer questions on Wednesday, Trump’s statement continued: “I once asked, ‘If you’re innocent, why are you taking the Fifth Amendment?’ Now I know the answer to that question … When your family, your company, and all the people in your orbit have become the targets of an unfounded politically motivated witch hunt supported by lawyers, prosecutors and the fake news media, you have no choice.”

As vociferous as Trump has been in defending himself in written statements and on stage at political rallies, legal experts said answering questions in a deposition was risky because anything he said could be used against him in Bragg’s investigation.

The fifth amendment protects people from being compelled to be a witness against themselves in a criminal case.

When the state investigation wraps up, James could seek financial penalties against Trump or his company, or even a ban on their involvement in certain types of businesses – as happened in a previous legal clash with James when, in 2019, the-then president was fined $2m for misuse of charitable assets and barred from running a charity in the future.

The Associated Press contributed reporting

• This article was amended on 10 August 2022. An earlier version stated that Donald Trump gave onlookers a thumbs-up after his deposition; it was before the deposition.