WASHINGTON (Reuters) — The acting Pentagon chief said on Monday the FBI is assisting the U.S. military in vetting more than 25,000 National Guard troops being deployed to assist in protecting the U.S. Capitol around President-elect Joe Biden’s inauguration for potential security concerns.

After the Jan. 6 Capitol assault by supporters of President Donald Trump that resulted in five deaths and sent lawmakers into hiding, the U.S. government has imposed unprecedented security surrounding the Capitol, including non-scalable fences rimmed with razor wire and a large security zone that the public is barred from.

Acting Secretary of Defense Christopher Miller said in a statement on Monday the vetting is “normal for military support to large security events… While we have no intelligence indicating an insider threat, we are leaving no stone unturned in securing the capital.”

Miller said he appreciated “the support of the FBI in assisting with this task and for each of the more than 25,000 Guardsmen.”

As is normal for military support to large security events, the Department will vet National Guardsmen who are in Washington, D.C. While we have no intelligence indicating an insider threat, we are leaving no stone unturned in securing the capital. This type of vetting often takes place by law enforcement for significant security events. However, in this case the scope of military participation is unique. The D.C. National Guard is also providing additional training to service members as they arrive in D.C. that if they see or hear something that is not appropriate, they should report it to their chain of command. We appreciate the support of the FBI in assisting with this task and for each of the more than 25,000 Guardsmen who answered their Nation’s call and rapidly deployed to the NCR.

Acting Secretary of Defense Christopher Miller

The U.S. Army said on Tuesday it was working with the FBI to see if any attackers were current service members and with the Secret Service to see if any of the nearly 10,000 National Guard troops securing Biden’s inauguration would need additional screening.

Asked why authorities were looking into the background of every National Guard member called in to help secure the area around the swearing-in ceremony, Acting Department of Homeland Security Secretary Peter Gaynor said on Monday, “The FBI and others decided this would be a prudent move.”

He told Fox News he has not seen any evidence of some sort of inside attack being planned, but authorities wanted to leave “no stone unturned” when it comes to potential threats to the peaceful transfer of power.

The U.S. government has for days blocked access to major public parks including Washington’s National Mall and closed bridges crossing the Potomac River between Virginia and the District of Columbia. More than a dozen subway stations have been closed through Wednesday’s inauguration.

At least one bus company has halted bus trips to Washington ahead of the inauguration, while Airbnb canceled home-sharing reservations in the Washington D.C. area for the week of Biden’s inauguration. U.S. airlines have also imposed new security precautions for DC-area flights.

Reporting by David Shepardson; additional reporting by Doina Chiacu

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