BREAKING: Capitol on lockdown due to "external security threat"; Update: Video added; Update: Literally a dumpster fire? Update: Propane tank explosion

Here we go again? Reporters inside Capitol Hill have been warned to stay away from doors and windows and part of the complex has been evacuated. The entire complex is now on lockdown due to an “external security threat,” which might be under a nearby bridge or underpass:

Something suspicious might have been spotted at the interstate highway that passes the complex:

This doesn’t appear related to any potential mob action, which would be tough to pull off at this point with the National Guard on duty and fences around the complex. It also doesn’t appear related to a fire located in the area, although the smoke apparently unnerved some inside:

We’ll have more as this develops. However, it’s worth noting that the FBI might not be entirely comfortable with the security arrangements for the inauguration. They have begun vetting the National Guard troops in advance of Wednesday’s events for extremist ties, although they have no evidence of any trouble yet:

U.S. defense officials say they are worried about an insider attack or other threat from service members involved in securing President-elect Joe Biden’s inauguration, prompting the FBI to vet all of the 25,000 National Guard troops coming into Washington for the event.

The massive undertaking reflects the extraordinary security concerns that have gripped Washington following the deadly Jan. 6 insurrection at the U.S. Capitol by pro-Trump rioters. And it underscores fears that some of the very people assigned to protect the city over the next several days could present a threat to the incoming president and other VIPs in attendance.

Army Secretary Ryan McCarthy told The Associated Press on Sunday that officials are conscious of the potential threat, and he warned commanders to be on the lookout for any problems within their ranks as the inauguration approaches. So far, however, he and other leaders say they have seen no evidence of any threats, and officials said the vetting hadn’t flagged any issues that they were aware of.

In other words, this additional vetting is evidence of an abundance of caution, not of an actual known problem. The security alert might be something different. Stay tuned.

Update: CBS News has the first video report:

They don’t have many other details yet, other than reporters were ordered back to their media trailers. Police then ordered them out of the trailers and to a “more secure location.”

Update: NBC’s Pete Williams reports that it actually was a fire in a homeless encampment that triggered the security alert. The AP also reports the same thing:

This could still be a diversion, so expect the lockdown to continue for a while. The two pipe bombs found outside the RNC and DNC offices on January 6th were likely a diversion too, and the Capitol Hill police aren’t going to take anything for granted.

Update: Here’s more on the fire:

If that’s all this was, perhaps next time it would just be best to alert outside security personnel first.

Update: This makes the security lockdown look a bit more sensible. It wasn’t the fire, Politico’s Lara Seligman reports, but an explosion caused by a propane tank in the camp:

Maybe DC and Capitol Hill police might consider relocating the camp for the next few days?