Lawmakers probing the 2021 attack on the US Capitol have subpoenaed former president Donald Trump to testify on his involvement in the violence, in a major escalation of their sprawling inquiry.
"As demonstrated in our hearings, we have assembled overwhelming evidence, including from dozens of your former appointees and staff, that you personally orchestrated and oversaw a multi-part effort to overturn the 2020 presidential election and to obstruct the peaceful transition of power," the committee told Trump in a letter on Friday.
The letter accuses Trump of bidding to overturn the election despite knowing claims of fraud had been overwhelmingly rejected by more than 60 courts and refuted by his campaign staff and senior advisors.
"In short, you were at the centre of the first and only effort by any US president to overturn an election and obstruct the peaceful transition of power, ultimately culminating in a bloody attack on our own Capitol and on the Congress itself," it added.
"We recognise that a subpoena to a former president is a significant and historic action,” Chairman Bennie Thompson and Vice Chair Liz Cheney wrote in the letter to Trump. "We do not take this action lightly."
The summons came after the House panel of seven Democrats and two Republicans voted unanimously last week to compel Trump's appearance before investigators.
It requires the 76-year-old Republican to produce documents by November 4 and to appear for a deposition beginning on or around November 14 -- the Monday after the crucial November 8 midterm elections.
Trump, who urged his supporters to "fight like hell" in a fiery speech near the White House on January 6, 2021, was impeached for inciting the mob to storm Congress later that day to halt the peaceful transfer of power to Joe Biden.
READ MORE: Trump subpoenaed for testimony on US Capitol attack
The subpoena issued to former US President Donald Trump by The House of Representatives Select Committee to Investigate the Capitol riots, ordering him to appear before the committee to testify.
Aggressive escalation
Subpoenas from the panel have proved difficult to enforce, with former White House aide Steve Bannon the only target convicted of contempt of Congress for refusing to comply.
Bannon was sentenced to four months in prison on Friday, although he remains out on bail pending an appeal.
It remains highly unlikely that he would agree to give evidence.
The subpoena expires in any case with the new congressional term in January.
Republicans are expected to win back the House of Representatives in November's elections and plan immediately to end the investigation.
But the move marks an aggressive escalation of the probe, which has issued more than 100 subpoenas and interviewed more than 1,000 people since its launch in 2021.
While no sitting president has ever been forced to testify before Congress, lawmakers have summoned several former presidents to discuss their conduct in office.
If Trump refuses to comply, the full House can hold him in criminal contempt in a vote recommending him for prosecution, as it did with Bannon.
READ MORE: Witnesses testify 'irate' Trump demanded to join Capitol mob