US Capitol Photograph:( AFP )
The troops remained in Washington for months after the inauguration as what many dubbed an insurrection was investigated
US Capitol stood unprotected by National Guard for the first time in about five months on Monday. Last 2149 out of 26,000 troops departed on Monday their mission to protect Congress formally ended.
The troops were mobilized after hundreds of supporters of then-president Donald Trump stormed the Capitol, halting the joint session to confirm Trump's rival Joe Biden as winner of the presidential election.
Some broke into lawmakers' offices, and called for the killing of lawmakers and vice president Mike Pence, who was presiding over the session.
Amid fears of more threats around and following the January 20 inauguration of Biden, thousands of Guard troops were mobilized, patrolling the Capitol area day and night while a large fence encircled the grounds, making it appear a building under siege.
The troops remained in Washington for months after the inauguration as what many dubbed an insurrection was investigated.
Trump, who was impeached for encouraging the assault, later claimed the attackers were "zero threat" to lawmakers and downplayed the episode.
The FBI has arrested and charged about 440 people involved in January 6 attacks. Dozens of them are associated with armed militia groups.
(With inputs from agencies)