(CNN) — The House select committee investigating the January 6, 2021, US Capitol attack voted to subpoena former President Donald Trump for documents and testimony during a public hearing Thursday.

The move is a significant escalation by the panel that will set up a showdown with the former President.

It is not expected that Trump will comply with the subpoena, but the action serves as a way for the committee to set down a marker and show that it wants information directly from Trump as the panel investigates the attack. The vote took place at the end of Thursday’s hearing.

The subpoena will surely trigger a prolonged court battle over Trump’s possible compliance, which could even outlast the committee itself. Republicans have pledged to shut down the Democratic-run panel if they retake the House majority in the midterm election next month.

Trump has previously derided the panel as an “Unselect Committee of Political Thugs and Hacks” and said its members are “evil, sinister and unpatriotic.” He has also complained that the committee’s “partisan kangaroo court” proceedings have “allowed no due process, no cross-examination and no real Republican members of witnesses to be present or interviewed.”

At the beginning of the hearing, Democratic Rep. Bennie Thompson of Mississippi, who chairs the committee, announced that the committee has changed Thursday’s public hearing to a business meeting, which is a technical difference but means the committee can vote on investigative actions.

NBC was first to report on the plan.

Thursday’s hearing is expected to be the final one before the midterm elections.