A militia group is allegedly plotting to storm Capitol Hill March 4 -the inauguration day of American leaders who took office before the 20th amendment of the Constitution in 1933.
QAnon has been pushing the idea that former U.S. President Donald Trump will return to power March 4.
U.S. Capitol Police said it had obtained intelligence that "an identified militia group" was planning a potential infiltration of the Capitol Thursday.
Social media sites have been cracking down on QAnon-related posts - but the number of believers has been growing in the U.S. The theory is unfounded but suggests Trump is preparing to take down Satan-worshipping child sex offenders - including those in the government.
Among the American presidents who were inaugurated March 4 were Andrew Jackson in 1829, Abraham Lincoln in 1861 and Warren G. Harding in 1921.
President George Washington's inauguration was initially scheduled for March 4, 1789. However, electoral ballot counting took longer than expected and Washington's travel time also delayed his inauguration until April 30.
Because of the threats the House pushed its voting to Wednesday night from Thursday.
The Capitol police have increased security following information from the Department of Homeland Security and the FBI said the activities of extremists.
Despite intensified security around Capitol Hill, law enforcement sources with knowledge of the matter said it was unclear if online discussions between extremists will be acted upon by March 4.
Sen. Alex Padilla said he and others were taking the DHS and FBI warnings "very seriously."
The Grand Hyatt Washington is sold out for March 4. During the Jan. 6 attack that resulted in the deaths of five people, a video of Trump supporters without masks in the hotel's lobby went viral.
Other hotels near Capitol Hill have rooms available.