Acting Homeland Security Secretary Peter Gaynor told "America Reports" Monday that there is a "heightened sense of alert" surrounding the security preparations for Joe Biden's inauguration amid reports U.S. defense officials are concerned about a potential insider attack from service members brought in to protect the transfer of power.

Washington, D.C. is taking a defensive posture ahead of Inauguration Day. Approximately 25,000 National Guard troops have been sent to the capital. at the behest of the Secret Service. 

According to the Associated Press, Army Secretary Ryan McCarthy said on Sunday that officials are alert for a potential threat.

Gaynor said that following the deadly Jan. 6 riot at the Capitol, the FBI determined it would be a "prudent move" to vet each National Guard soldier sent to defend the inauguration.

BIDEN INAUGURATION SECURITY: WHAT TO KNOW AS DC LOCKS DOWN

GAYNOR: "You know, there is some chatter out on the Internet about those that seek to disrupt the peaceful transfer of power on the 20th, and the FBI and Secret Service and all our partners, the intel community, are looking into that to make sure that, again, no stone [is] unturned when it comes to somebody's thinking about threatening the peaceful transfer of power."

GAYNOR: "After the 6th of January, everyone is [on] heightened alert. What happened on the 6th is absolutely uncalled for. You know, it's horrible in our history. And to make sure that, again, we have a peaceful transfer of power, we want to make sure that, you know, we don't wish we didn't go far enough. [We have an] impressive array of men and women out there ready to make sure that that transfer happens peacefully."

The presidential inauguration is designated as a recurring National Special Security Event (NSSE). When an event is given this designation, the Secret Service becomes the lead federal agency responsible for coordinating security for the event. 

CLICK HERE TO GET THE FOX NEWS APP"

So, far, no threats have been identified and no issues have been reported in the vetting process

Matt Miller, the special agent in charge of the Secret Service, said the city has extended the special designation for security from Jan. 13 to Jan. 21, the day after President-elect Joe Biden is sworn in. 

Fox News' Brian Flood contributed to this report.