(Bloomberg) -- A group of House Republicans Wednesday released their long-promised counter-report to the House Select Committee investigating the Jan. 6, 2021, Capitol assault, one that partly blames Democratic congressional leaders for security failures.

The 78-page report, with as many added pages of appendices and footnotes, declares itself a supplement to the June 2021 findings of a previous joint investigation by two Senate committees. It breaks little new investigative ground, with its main finding that intelligence and law enforcement failures left the US Capitol complex vulnerable.

But the report does add emphasis to Democratic Speaker Nancy Pelosi’s role in the Capitol security plan before the insurrection. 

The report claims that the House committee looking into the insurrection, which is set to release its full report on Thursday, has disregarded some of this information. That panel concluded in a summary of its findings released Monday that then-President Donald Trump was “the central cause” of last year’s Capitol insurrection as he sought to prevent the peaceful transfer of power to Joe Biden.

“There are several reasons the Capitol was left unprepared on Jan. 6, 2021, including internal politics and unnecessary bureaucracy,” the authors of the Republican report said, citing emails and other internal communications. 

“Then-House Sergeant at Arms Paul Irving — who served on the Capitol Police Board by virtue of his position — succumbed to political pressures from the Office of Speaker Pelosi and House Democrat leadership leading up to Jan. 6, 2021,” according to the report, which also underscores that House Republican lawmakers were excluded from “important discussions” about security planning before Jan. 6.

“But rather than coordinate in a meaningful way, Irving only provided information to Republicans after receiving instruction from the speaker’s office,” the report asserts. “In one case, Irving even asked a senior Democratic staffer to ‘act surprised’ when he sent key information about plans for the Joint Session on Jan. 6, 2021, to him and his Republican counterpart. The senior Democratic staffer replied: ‘I’m startled!’”

Though the report’s focus was on Democrats, Republicans who then controlled the Senate also had representation on the Capitol Police Board, through the Senate sergeant at arms. The Jan. 6 committee’s report is also expected to feature a section on security.

The report reiterates that federal law enforcement and intelligence agencies had received specific warnings in December 2020 of potential and significant violence related to the Jan. 6 certification of the 2020 election results.

The report also reiterates former Capitol Police Chief Steven Sund’s claim that Irving said “optics” were the reasons House and Senate security officials gave for denying his request that the National Guard be placed on standby in the days before the riot. 

It notes a March 2022 General Government Accountability Office report’s findings that there were concerns regarding the use of force at the Capitol, including “a concern with optics by leadership” and that “several respondents stated that the concern with optics was related to leadership’s perception of the desires of members of Congress.”

Irving, when asked during a Feb. 23, 2021 Senate hearing whether consulting with congressional leaders delayed National Guard deployment, responded: “Absolutely not,”

The report was released by House GOP Leader Kevin McCarthy and representatives Rodney Davis of Illinois, Jim Banks of Indiana, Troy Nehls of Texas, Jim Jordan of Ohio and Kelly Armstrong of North Dakota. 

“This report answers what the American people have asked since day one: why the Capitol was so unprepared — and it outlines a plan for a more secure Capitol in the 118th Congress,” McCarthy said in a tweet.

There was no immediate comment from a Pelosi spokesman.

©2022 Bloomberg L.P.