Everyone was ordered back inside and instructed to stay away from windows and doors and seek cover if outside.
The good news -- the D.C. Fire Dept. located the fire and put it out ... and nobody was hurt. Our sources say the fire was started at a homeless encampment and is no longer viewed as any sort of threat.
Of course, there is a very strong security presence everywhere in the area -- bolstered by some 20,000 National Guard troops -- and the brief evacuation is a sign of the high alert that remains since the Jan. 6 Capitol riots.