The US Department of Justice on Friday ordered the Internal Revenue Service to hand Donald Trump’s tax returns to a House committee, saying the panel had “invoked sufficient reasons” for requesting them.

The news was a second blow for Trump in a matter of hours, after released DoJ memos revealed that as part of his campaign to overturn his election defeat by Joe Biden, he pressured top officials to falsely label the 2020 election as corrupt, then “leave the rest to me”.

House speaker Nancy Pelosi applauded the DoJ’s order to the IRS to release Trump’s tax returns to the ways and means committee.

“Today, the Biden administration has delivered a victory for the rule of law, as it respects the public interest by complying with Chairman [Richard] Neal’s request for Donald Trump’s tax returns,” Pelosi said in a statement.

“Access to former President Trump’s tax returns is a matter of national security. The American people deserve to know the facts of his troubling conflicts of interest and undermining of our security and democracy as president.”

Candidates for president traditionally disclose their tax returns, although they are not legally compelled to do so. Trump kept his out of the public eye when he ran for the White House in 2016, saying they were under IRS audit, and did not release them while in office.

Once Democrats took control of the House in 2018, amid the investigation of Russian election interference and links between Trump and Moscow by the special counsel, Robert Mueller, they began to seek the records in court.

Trump fought hard to keep his tax returns out of the public eye but the New York Times obtained some of the records, which showed Trump paid almost nothing in federal income taxes in the years before he entered the White House.

In a memo on Friday, the DoJ Office of Legal Counsel said Neal, the Massachusetts congressman who chairs the ways and means committee, had “invoked sufficient reasons for requesting the former president’s tax information”.

Under federal law, the OLC said, the Department of the Treasury “must furnish the information to the committee”.

The 39-page memo was signed by Dawn Johnsen, installed by the Biden administration as the acting head of the OLC.

Trump’s treasury secretary, Steven Mnuchin, said he would not turn over Trump’s tax returns because they were being sought for partisan reasons.

The House ways and means committee sued for the records under a federal law that says the IRS “shall furnish” the returns of any taxpayer to a handful of top lawmakers. The committee said it needed Trump’s taxes for an investigation into whether he complied with tax law.

Trump’s justice department defended Mnuchin’s refusal and Trump intervened to try to prevent the materials from being turned over to Congress. Under a court order from January, Trump would have 72 hours to object after the Biden administration formally changes the government’s position in the lawsuit.

Bill Pascrell, a New Jersey Democrat who chairs the House ways and means subcommittee on oversight, said: “It is about damn time. Our committee first sought Donald Trump’s tax returns on 3 April 2019 – 849 days ago. Our request was made in full accordance with the law and pursuant to Congress’s constitutional oversight powers.”

Daniel Goldman, an attorney who counselled Democrats during Trump’s first impeachment inquiry and trial, said: “The former OLC opinion supporting Mnuchin’s ability to withhold Trump’s tax returns was perhaps the most egregious and baseless opinion of many bad ones during the Trump era.”

Michael Stern, a former senior counsel for the House Office of General Counsel, told Politico Trump had options to stop the release of his returns.

“I think Trump will be given an opportunity to either file a new case or file something in this case in which he states his legal grounds for objecting to his tax returns being produced,” he said, adding: “It’s definitely not over yet.”

Elsewhere, the Manhattan district attorney, Cyrus Vance Jr, has obtained copies of Trump’s personal and business tax records as part of a criminal investigation.

Trump tried to prevent his accountants from handing over the documents, taking the issue to the supreme court. The justices rejected Trump’s argument that he had broad immunity as president.

Speaking to Reuters about the DoJ order, Richard Painter, a University of Minnesota law professor who was ethics counsel to George W Bush, said it seems the Biden justice department “is no longer going to simply kowtow to Donald Trump”.

“Every other president has disclosed their tax returns” he said, “and finding out what the conflicts of interest are on the president or a former president who may have made decisions that now have to be revisited – that’s critically important.”