US lawmakers demanded more information on the potential threat to national security posed by Donald Trump’s hoarding of classified documents, as the fallout from the unprecedented search at the home of the former president reverberated through Washington.

The comments by Democrats and Republicans on Sunday were among the first reactions from Congress to the release on Friday of the search warrant presented by the FBI on the day of the visit on August 8, revealing that Trump was being investigated for serious violations of the law related to national defence, the mishandling of government material and obstruction of justice.

They highlighted the sharp partisan divide with regards to Trump’s treatment by US law enforcement, with Democrats focusing on the legal gravity of his behaviour and Republicans sceptical and critical of the search.

Adam Schiff, the top Democrat on the House intelligence committee, has asked the director of national intelligence to review the harm to American interests — formally known as a damage assessment — resulting from Trump’s decision to hold on to a trove of sensitive material after leaving the White House in early 2021.

“What is, to me, most disturbing here is the degree to which . . . it appears to be wilful, on the president’s part — the keeping of these documents after the government was requesting them back. And that adds another layer of concern,” Schiff said.

Republicans, many of whom have rushed to Trump’s side and attacked the Department of Justice, the FBI and US attorney-general Merrick Garland over the past week, asked federal authorities to release the affidavit in support of the search warrant. Affidavits, which typically remain under wraps throughout a federal investigation, contain details on the reasons why the DoJ asked a federal judge to approve the search.

“All Garland has to do is comply with the laws, provide this information to us, let us look. Show us the goods,” Mike Turner, the top Republican on the House intelligence committee, said on CNN. “We need to determine, is this a national security threat? And . . . was there abuse of discretion by attorney-general Garland?,” he said.

“I think it’s very important long-term for the justice department, now that they’ve done this, that they show that this was not just a fishing expedition — that they had due cause to go in and to do this, that they did exhaust all other means. And if they can’t do that, then we’ve got a serious problem on our hands,” Mike Rounds, a Republican senator from South Dakota, told NBC.

Trump has maintained that the search was a politically motivated stunt, claiming to have declassified all the material before leaving office, though there is no record of such a step. According to the inventory of 45 items recovered by the FBI at Trump’s Mar-a-Lago estate in Florida, 11 were described by the authorities as being either top secret, secret, classified, or confidential.

On Sunday, the former president said the boxes retrieved by the FBI contained items protected by attorney-client privilege. “I respectfully request that these documents be immediately returned to the location from which they were taken,” he wrote on his Truth Social account.

The harsh criticism from the former president and his Republican allies has raised fears of violence against the FBI and DoJ. The Department of Homeland Security and the FBI issued a joint bulletin on Friday about the potential for attacks on law enforcement personnel and facilities across America as anger has flared among Trump’s conservative base of supporters who already deeply mistrust the federal government.

The White House has sought to distance itself from the search of Trump’s property and continued to do so on Sunday. Even when asked to comment about the latest revelations that the material recovered from Trump may pose a risk to national security, Karine Jean-Pierre, the White House press secretary, said: “We do not interfere. We do not get briefed. We do not get involved.”

But congressional Democrats were less restrained.

“When I look at classified documents, I’ve got to go in a special room. I can’t even wear my Fitbit. You can’t bring staff with you. And that’s because these documents not only contain our nation’s top secrets but because countries that will do us harm, do harm to our own citizens, we don’t want them to get a hold of them in any way,” said Amy Klobuchar, the Democratic senator from Minnesota, told NBC.

“That’s why it is so important that these documents remain in safe locations. And Mar-a-Lago, where you can check out croquet sets and tennis rackets and golf clubs, that’s not one of them,” she added.