The House Special Committee investigating the deadly January 6th Capitol riot announced Thursday that it had issued subpoenas to four of former President Donald Trump’s closest allies, including his former chief of staff Mark Meadows and former close adviser Steve Bannon.

The subpoenas, which were also sent to former White House Deputy Chief of Staff Daniel Scavino and former Defense Department official Kashyap Patel, instruct witnesses to produce materials by October 7 and to appear at the testimony in the coming weeks the committee said in a press release.

The committee directed Bannon and Patel to attend their testimony on October 14th, while Meadows and Scavino’s testimony is scheduled for October 15th.

The subpoenas mark a sharp escalation in the committee’s investigation into a final analysis of the January 6 invasion in which hundreds of Trump’s supporters forced Congress to go into hiding and temporarily shut down the process of confirming President Joe Biden’s victory Failed.

“The committee is investigating the facts, circumstances and causes of the attack on the 6th. Bennie Thompson, D-Miss., The chairman of the committee, in a statement Thursday.

White House Chief of Staff Mark Meadows speaks to reporters at the White House on October 21, 2020 in Washington, DC.

Tasos Katopodis | Getty Images News | Getty Images

A Meadows spokesman declined CNBC’s request for comment. A spokeswoman for Bannon did not immediately respond to a request for comment.

Trump spokesman Taylor Budowich said in a statement that the “communist-style” summons from the House of Representatives were too broad and unfounded.

“Executive privilege is being defended not only on behalf of President Trump and his administration, but also on behalf of the office of the President of the United States and the future of our nation,” Budowich said. “The fake news continues to lure the Democrats desperately trying to distract the country with this fake trial.”

In another, much longer statement, sent out later Thursday evening, Trump criticized the committee and the Biden administration and reiterated the false claim that the 2020 elections he lost were “manipulated” against him.

“Hopefully the Unselect Committee will name witnesses to the rigged 2020 presidential election, which is the main reason hundreds of thousands of people went to Washington, DC in the first place,” Trump said.

The announcement comes two days after Rep. Adam Schiff said the committee would summon some witnesses as an initial measure if they prove resistant or hostile to the panel’s goals.

In individually addressed letters, Chairman Thompson explained why the witnesses believed to have relevant information for the committee’s investigation.

A letter to Meadow said he was “involved in several elements” to challenge the 2020 presidential election results and delay the counting of votes.

The letter also noted that Meadow was in contact with the organizers of the January 6 riot, including Women for America First’s Amy Kremer, and cited Justice Department documents showing that he had sought electoral fraud investigations in several states.

Former White House chief strategist Steve Bannon leaves the Manhattan Federal Court after being charged with conspiracy to commit wire fraud and conspiracy to commit money laundering in New York on August 20, 2020.

Andrew Kelly | Reuters

As for Bannon, a letter described his efforts to convince members of Congress to block the confirmation of the election at the Willard Hotel on Jan. 5, citing Bob Woodward’s book on the Trump administration. It also noted that on December 30th, Bannon had urged the former president to “focus his efforts” on January 6th.

A letter to Scavino underscored his ten-plus years of service with Trump and detailed his knowledge of the former president’s plans that led to the January 6 uprising. The committee was said to be looking for material Scavino may have that is relevant to Trump’s “video recordings and Twitter messages” on January 6th.

White House Assistant Chief of Staff for Communications Dan Scavino speaks in a recorded speech at the Andrew W. Mellon Auditorium in Washington, DC, ahead of the Republican National Convention on August 26, 2020.

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The letter also quoted Scavino’s own posts on Twitter promoting “January 6 for Trump” and encouraging people to “be part of the story”.

As for Patel, a letter alleged that the committee had good reason to believe it had additional materials that could help them understand the roles of the Department of Defense and the White House in preparing and responding to the insurrection.

Kash Patel, Chief of Staff to Acting Secretary of Defense Christopher Miller, center, in the U.S. Capitol in Washington, DC, USA on Sunday, January 17, 2021.

Graeme Sloane | Bloomberg | Getty Images

It also noted that Patel was involved in talks with senior Defense Department officials on Jan. 6 about the security of the U.S. Capitol.