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Some 25,000 National Guard troops are being dispatched to Washington, D.C., this week ahead of President-elect Joe Biden's inauguration ceremony Wednesday, and the Federal Bureau of Investigation plans to subject all of them to additional vetting amid concerns of an "insider attack," The Associated Press reports.

Law enforcement agencies routinely scrutinize service members to root out those with any potential links to extremist views. But as AP reports, this practice has for years focused on "homegrown insurgents radicalized by al-Qaida, the Islamic State group, or similar groups." In this case, though, the FBI is worried about troops who might harbor animus toward the incoming administration "fueled by supporters of President Donald Trump, far-right militants, white supremacists, and other radical groups."

Trump has been widely blamed for inciting the violent insurrection attempt on the U.S. Capitol earlier this month, which left five people dead. Ongoing threats of violence have led to increased security in Washington — where the National Mall will be closed for Inauguration Day — and around the country.

Military and law enforcement personnel have been running drills in preparation for Inauguration Day, studying maps of the D.C. area, and plotting their routes. The FBI vetting process for National Guard members will likely involve scanning databases and watch lists for red flags, AP reports. Troops are also being trained on how to spot threats within their ranks.

"The question is, is that all of them? Are there others?" asked Army Secretary McCarthy. Read more at AP.