DC National Guard Guardsmen stand outside the U.S. Capitol in Washington, DC on January 7, 2021.
John Moore | Getty Images
WASHINGTON – Army Secretary Ryan McCarthy said Thursday that intelligence law and defense officials were "everywhere" prior to the uprising that rocked Washington.
"There were estimates of 80,000, there were estimates of 20-25. So back to sheer intelligence. It was all across the board," McCarthy explained when asked about crowd control preparations.
"It has been very difficult to make that decision about what you are up against," he told reporters on a call, adding that the Department of Defense relies on law enforcement threat assessments.
By the weekend, 6,200 National Guard employees will be stationed in the country's capital and will stay in the region for at least 30 days. The month-long mobilization ensures that members of the National Guard will be present for President-elect Joe Biden's inauguration on January 20.
The unarmed forces will monitor traffic checkpoints and assist with law enforcement, while authorities work to secure the perimeter of the Capitol the day after the storm by a mob supporting President Donald Trump.
Pro-Trump supporters storm the U.S. Capitol following a rally with President Donald Trump on January 6, 2021 in Washington, DC.
Samuel Corum | Getty Images
The mobilization comes as the nation processes Wednesday's surprise uprising that killed at least four people. All four living former presidents have condemned the day's events, where a violent mob discouraged lawmakers from the typically superficial process of formally confirming Biden's victory.
The DC National Guard was mobilized during the riot and about 1,100 soldiers were deployed to assist local police in containing the insurgency, the Pentagon said. The operation came after Washington D.C., Mayor Muriel Bowser and House Speaker Nancy Pelosi requested the force, two sources told NBC News.
Ralph Northam, governor of Virginia, Larry Hogan, governor of Maryland, and Andrew Cuomo, governor of New York, announced all plans to send National Guard troops to DC as well.
Trump, who spoke at a rally to protest the election results just before his supporters infiltrated Congress, has still not condemned the unrest or defeat.
He encouraged protesters to be peaceful after storming the Capitol.
Pro-Trump protesters storm the U.S. Capitol to challenge the U.S. Congress certifying the 2020 U.S. presidential election results at the U.S. Capitol Building in Washington, DC on January 6, 2021.
Ahmed Gaber | Reuters
The President has continued to raise unsubstantiated allegations of electoral fraud despite the findings of the Justice and Homeland Security Ministries to the contrary.
It is typical for the National Guard to be present at the inaugurations, and in 2017 more than 7,000 soldiers were mobilized for Trump's inauguration.
Biden's inauguration is expected to look very different from previous ceremonies due to public health precautions.
Biden and Vice President-elect Kamala Harris will take their oath of office at the Capitol on Jan. 20, but have otherwise changed tradition to adapt to the spreading coronavirus pandemic.
The Biden transition team has said it is reinterpreting the typical National Mall gathering and opening parade from the Capitol to the White House so that Americans can attend from home.
Biden condemned the riot on Wednesday in a national televised address.
"At this hour our democracy is being attacked in an unprecedented manner," said the former vice president.
"It's chaos, it verges on turmoil and it has to end now. I call on this mob to pull out and do this democratic work," added Biden.
The rioters' success in breaking police barriers has raised questions about the security precautions being taken for the inauguration.
Senator Amy Klobuchar, D-Minn., Who is on the committee planning Biden's inauguration, said on CBS News, "There are going to have to be big, big reviews of what happened and what changes have been made."
Klobuchar added that the inauguration is a major security event every four years compared to the electoral college vote count, which generally takes place without incident.
"Here they had an event that normally has little historical note," said Klobuchar.
CNBC's Tucker Higgins reported from New York.
Subscribe to CNBC Pro for the live TV stream, deep insights and analysis of how to invest during the next president's term.