The National Guard are on a 24-hour watch in the US Capitol after last week's violence, with off-duty members left to catch naps in hallways and below the bust of General George Washington, who led the United States to victory in its battle for independence against Britain more than two centuries ago.
A large presence of guard members dressed in fatigues and carrying rifles guarded the outside the building on Wednesday, while others lined the corridors of the Capitol.
The House of Representatives was meeting to consider impeaching President Donald Trump for his role in the January 6 assault on American democracy, when his supporters stormed the building in a deadly rampage.
While National Guard troops have been stationed inside and outside the seat of Congress since at least Friday, earlier they had not been armed with rifles.
Now, some of the 20,000 National Guard troops ordered to Washington to secure the city before President-elect Joe Biden's inauguration on January 20 have weapons in hand. Riot shields and gas masks are piled in the hallways.
New fencing and other security measures have also gone up around the building that is seen by many as an important global symbol of democracy. A two-metre high fence has been erected around the Capitol, with metal barriers and National Guard troops protecting the congressional office buildings that surround it.
"The attack on the Capitol was a violent insurrection that resulted in the spilling of American blood," said US Representative Hakeem Jeffries, a Democrat from New York. "And that's why extraordinary security measures have been taken.
"Officers were brutally beaten. The attackers wanted to assassinate Nancy Pelosi, hang Mike Pence, and hunt down sitting members of Congress. That's insurrection. That's sedition. That's lawlessness. That's terror," Jeffries said.
National Guard troops have been frequently used by states in helping law enforcement forces quell protests in the past year. However, the decision to arm them with guns highlights fears over the threat of further violence in the days leading up to the inauguration.
Officials have said it is important for the troops to be armed for their self defence and that they are still in a support role of law enforcement forces.
Australian Associated Press