At least 25 people are under investigation on terrorism charges related to Wednesday's siege at the Capitol, according to a Defense official and a member of Congress.

Rep. Jason Crow, a Democrat of Colorado and a former Army Ranger, said he spoke with Army Secretary Ryan McCarthy on Sunday and was told that "at least 25 domestic terrorism cases have been opened as a result of the assault on the Capitol."

A defense official who was informed about the call initially confirmed that the cases involved troops but later corrected that statement. The official said some troops – active and reserve duty – may have been involved in the riot, and the military will investigate them as necessary.

"There is concern that military members may have been involved in the riot," the official said.

Those under investigation are suspected of taking part in the insurrection that shut down Congress as it formalized President-elect Joe Biden's Electoral College victory. Five people died, including a Capitol Hill police officer, after the pro-Trump mob overwhelmed security lines.

“We are engaged in identifying all of those who took part in breaching the Capitol, regardless of their affiliation,” Justice spokesman Marc Raimondi said Sunday.

Thousands of supporters of President Donald Trump marched to the U.S. Capitol on Wednesday in a demonstration that rapidly turned violent.

The Pentagon also has been asked to review all members who will be a part of the security detail for the inauguration Jan. 20 to ensure the are "not sympathetic to domestic terrorists," Crow said.

President Donald Trump encouraged thousands of his followers to march on the Capitol after he addressed them outside the White House on Wednesday.

Capitol riot live updates: More arrests, violence across US as Pope Francis condemns 'this movement' (USA Today)

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