• The House select committee investigating the Jan. 6 Capitol riot voted to subpoena former President Donald Trump during Thursday's public hearing.
• The move to subpoena Trump has been under consideration for some time, sources familiar with the committee's plans told NBC.
• The vote marks the boldest step yet for the bipartisan panel, which has so far issued more than 100 subpoenas and interviewed more than 1,000 people over the course of its investigation.

The House select committee investigating the Jan. 6 Capitol riot unanimously voted at its public hearing Thursday to subpoena former President Donald Trump about his actions surrounding the insurrection.

The move to try to force Trump to testify under oath has been under consideration for some time.

The vote marks the boldest step yet for the bipartisan panel, which has so far issued more than 100 subpoenas and interviewed more than 1,000 people over the course of its investigation.

Most of those witnesses have complied with the committee's requests. But Trump is thought to be highly unlikely to willingly cooperate with the panel, which he repeatedly decried as a politically motivated witch hunt.

"It is our obligation to seek Donald Trump's testimony," committee Chairman Rep. Bennie Thompson, D-Miss., said before the vote.

Vice Chair Rep. Liz Cheney, R-Wyo., who introduced the resolution for Thompson to issue the subpoena, said it is a "key task" of the committee to compel the testimony of "January 6th's central player."

She noted that, of the roughly 30 witnesses who have invoked the 5th Amendment right against self-incrimination during their testimony, several did so directly in response to questions about their dealings with Trump.

Those witnesses include Republican political operative Roger Stone, former Trump Justice Department official Jeffrey Clark, former national security advisor Michael Flynn and the pro-Trump attorney John Eastman, Cheney said.

She added that some key figures have defied subpoenas. They include Steve Bannon, a former senior aide in Trump's White House who was convicted of contempt of Congress for his refusal to testify.

Thompson clarified in his opening statement that Thursday's presentation is technically not a hearing, but a "formal committee business meeting" so members can potentially hold a vote on further investigative action.

Just before the hearing adjourned, the nine-member panel voted unanimously to direct Thompson to issue the subpoena for Trump.

Trump railed against the Jan. 6 probe in a flurry of angry statements and posts on his social media platform Truth Social later Thursday. "The committee is a total 'BUST' that has only served to further divide our Country," one post read.

The committee's ninth public hearing Thursday afternoon took a broad look at the findings from its investigation, interspersed with new clips and information.

The panel kept the spotlight on Trump as it played clips of his former staffers, who testified that they knew at the time that Trump had lost the 2020 election to President Joe Biden.

The hearing also showed new clips of House Speaker Nancy Pelosi, D-Calif., and others calling multiple Trump administration officials, including Vice President Mike Pence, to urge them to take action to quell the riot as they hid from the mob that overran the Capitol.

The committee is tasked with probing the facts and causes of the Jan. 6, 2021, riot, when a violent mob of Trump's supporters stormed the Capitol and forced lawmakers to flee their chambers for safety.

Trump, who never conceded the election to Biden, falsely claims that his victory was stolen through widespread voter fraud.