WASHINGTON — The House committee investigating the Jan. 6 attack on the Capitol voted unanimously Thursday to subpoena former President Donald Trump.

Members of the panel, which held what was expected to be its final hearing before the midterm elections Thursday, had previously said that they were still considering seeking an interview with Trump or former Vice President Mike Pence. Sources familiar with the committee’s plans told NBC News of the subpoena earlier Thursday.

The panel’s chair, Rep. Bennie Thompson, D-Miss., said the committee had an “obligation” to hear from Trump.

“This is a question about accountability to the American people. He must be accountable. He is required to answer for his actions. He’s required to answer to those police officers who put their lives and bodies on the line to defend our democracy. He’s required to answer to those millions of Americans whose votes he wanted to throw out as part of his scheme to remain in power,” Thompson said, acknowledging the move as a “serious and extraordinary action.”

The resolution to subpoena Trump passed with the support of all members, 9-0.

The resolution was introduced by the panel’s vice chair Rep. Liz Cheney, R-Wyo., who called Trump the riot’s “central player.”

A source familiar with the committee’s plans told NBC News the panel plans to issue the subpoena in the coming days.

The panel is on a tight timeframe — the subpoena will expire at the end of this congressional term, and Trump is likely to challenge it.

The subpoena comes more than a year after the committee began investigating the insurrection and despite multiple members of Congress previously acknowledging that it was unlikely Trump would comply.

Still, subpoenaing the former president had been under consideration for a while and has been an active topic of discussion among committee members. On his way to the hearing Thursday, Thompson told reporters the panel had not yet ruled out a subpoena for Trump.

Thompson said at the beginning of Thursday’s hearing that the panel had convened as a formal committee business meeting, so that, in addition to presenting evidence, “We can potentially hold a committee vote on further investigative action based upon that evidence.”

In its wide-ranging investigation, the panel has already conducted more than 1,000 interviews and depositions. It has also received hundreds of thousands of documents and some 100 subpoenas are known to have been issued.

Thursday’s hearing once again placed Trump at the center of plans to overturn the election — which ultimately led to the bloodshed on Jan. 6, Cheney said in her opening statement.

“None of this would have happened without him. He was personally and substantially involved in all of it,” she said. “Today, we will focus on President Trump’s state of mind, his intent, his motivations, and how he spurred others to do his bidding. And how another Jan. 6 could happen again if we do not take necessary action to prevent it.”

Cheney also said that the committee “may ultimately decide to make a series of criminal referrals to the Department of Justice,” though she said that lawmakers “recognize that our role is not to make decisions regarding prosecution.”

Trump would not be the first former president subpoenaed by Congress. Several sitting and former presidents and vice presidents have also testified before congressional committees, including Presidents Abraham Lincoln, Woodrow Wilson and Gerald R. Ford.

It’s unclear if the committee will seek to interview Pence, who blocked Trump’s effort on Jan. 6 to overturn the 2020 presidential election and who faced threats of being hanged that day.

In August, Pence said during an event in New Hampshire that he would consider testifying before the House Jan. 6 committee if invited to appear, but he suggested he would need to sort out some constitutional questions before committing.

“If ever any formal invitation were rendered to us, we’d give it due consideration,” he said.

Thompson had previously suggested that Thursday would be the committee’s final hearing, but several of its members recently have said that might not be the case.

When asked on MSNBC’s “Morning Joe” whether there will be additional hearings, Rep. Stephanie Murphy, D-Fla., said the investigation “has its own life, and we keep finding new information.”