US Capitol Police arrested a California man who had a bayonet and machete in his pickup truck outside of Democratic National Committee headquarters on Monday morning.
The man, Donald Craighead of Oceanside, California, had a swastika and other white supremacist symbols painted on his pickup and told officers he was "on patrol."
The arrest comes days before a Washington, DC rally on Saturday, September 18, where supporters of former president Donald Trump plan to gather outside the US Capitol to support the hundreds of people being prosecuted for their involvement in the January 6 riot.
It also comes on the eve of a recall election for California Governor Gavin Newsom at the hands of a Republican minority.
Saturday's rally organiser, Matt Braynard, a former Trump campaign strategist, has been promoting the event and others like it in cities nationwide.
Mr Braynard has been focusing attention on what he calls "political prisoners", or those arrested for the January 6 insurgence.
More than 600 people are facing federal charges in the riot that injured dozens of officers and sent legislators into hiding.
Five people eventually died, including Trump supporter Ashli Babbitt, who was shot and killed by police as she tried to break into a lobby off the House chamber. Several police officers later took their own lives.
Capitol Police said it was unclear if Craighead was planning on attending any demonstrations.
Authorities this year warned of possible violent acts in the run-up to the 9/11 anniversary and former president George W Bush railed against the divisions in America during a memorial event in Pennsylvania.