The surprise move came as the committee aired never-before-seen footage from the storming of Congress.
The US congressional committee investigating last year’s Capitol riot has issued a legal summons for former President Donald Trump to testify.
“He is required to answer for his actions,” said Representative Bennie Thompson, a Mississippi Democrat.
If Mr Trump does not comply with the summons, known as a subpoena, he could face criminal charges and imprisonment.
The select committee is looking into Trump supporters’ storming of Congress on 6 January 2021.
The panel’s seven Democrats and two Republicans voted 9-0 in favour on Thursday of issuing the subpoena for the former Republican president to provide documents and testimony under oath in connection with the Capitol riot.
Representative Liz Cheney, the committee’s vice-chairwoman and a Wyoming Republican, said: “We are obligated to seek answers directly from the man who set this all in motion. And every American is entitled to those answers.”
The surprise move came during the investigation’s ninth and possibly final public hearing for the investigation into last year’s raid on Congress.
At Thursday’s session the committee said it would focus on Mr Trump’s “state of mind” as he refused to admit defeat to Joe Biden in the presidential election of November 2020.
Mr Trump – who has lambasted the inquiry as a ruse designed to distract US voters from the “disaster” of Democratic governance – is widely expected to refuse to testify and fight the subpoena.
His former political strategist, Steve Bannon, also flouted a similar legal summons from the select committee to testify, and he was found guilty in July of criminal contempt of Congress.
On Thursday, Mr Trump questioned on his Truth Social platform why the committee had not asked him months ago to testify.
“Why did they wait until the very end, the final moments of their last meeting?” he posted. “Because the Committee is a total ‘BUST’ that has only served to further divide our Country which, by the way, is doing very badly – A laughing stock all over the World?”
The panel has spent more than a year interviewing over 1,000 witnesses, including Mr Trump’s children, his top aides and top military and police officials.
During Thursday’s hearing, the committee showed never-before-seen footage of Congress being evacuated as the building was breached, and lawmakers being moved to secure shelters.
Democratic Speaker of the House Nancy Pelosi, whose daughter filmed the video, is seen expressing shock when told that lawmakers in another part of the building were being told to wear gas masks.
She and other lawmakers are seen in the clip desperately calling military officials and the governors of nearby states in a plea for more resources to fight back the mob.
Mike Pence, Mr Trump’s vice-president, is heard on the phone speaking to Mrs Pelosi about how long it will be before lawmakers can return to the floor to resume voting on Mr Biden’s confirmation.
The committee also heard evidence that Mr Trump was aware that he had lost, but encouraged the conspiracy theory about a stolen election anyway.
White House communications aide Alyssa Farah said in videotaped testimony that about a week after the election Mr Trump was watching the news when he told her: “Can you believe I lost to this effing guy?”
One of the few remaining questions hanging over the 6 January hearings is whether the committee – which has accused Mr Trump of an attempted coup – will formally recommend criminal charges be brought against him.
The committee members have been guarded about whether they will issue any such conclusions on criminal culpability. Democrat Adam Schiff of California recently said any decision will have to be unanimous.
Earlier this year, there was some disagreement within the committee about whether a criminal “referral” was even under consideration, with committee chairman Bennie Thompson ruling it out – and Republican vice-chair Liz Cheney and others quickly disagreeing.
During Thursday’s meeting, she left the door open, saying the committee “may ultimately decide to do so”, but the panel’s role “is not to make decisions regarding prosecution”.
While any decision to prosecute – for contempt if Mr Trump refuses to testify, or a larger criminal charge – would be in the hands of justice department prosecutors, a committee referral could have symbolic importance as the final considered judgement of the bipartisan group.