Washington DC - A militia group likely inspired by the QAnon conspiracy theory has been plotting to attack the US Capitol on Thursday, according to a law enforcement intelligence assessment that prompted the House to cancel all legislative business out of safety concerns.

The assessment, which was disseminated to all members of Congress on Wednesday by Capitol Police, did not identify the group, but the timing of the alleged plot gives a clue.

Thursday is March 4 – the date followers of QAnon falsely believe Donald Trump will reclaim the presidency.

QAnon adherents, who ascribe to the baseless theory that Trump is on a secret mission to expose a Satanist cabal of Democratic pedophiles in control of the US government, picked March 4 because it was the original date for presidential inaugurations until 1933.

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With the deadly January 6 attack on the Capitol still fresh on their minds, House leaders canceled votes planned for Thursday and advised members they did not need to appear for session after the unnerving alert.

It appeared unlikely that the Senate, which is working on the coronavirus stimulus package, would cancel its Thursday session.

Capitol Police said they will beef up security on Thursday due to the potential threat.

"Based on the intelligence that we have, the Department has taken immediate steps to enhance our security posture," the agency said.

House Sergeant-at-Arms Timothy Blodgett also issued a memo Wednesday warning that there could be trouble into the weekend, with "additional interest in the Capitol for the dates of March 4-6 by a militia group."

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Several far-right militias, including the Oath Keepers and the Three Percenters, played a part in the January 6 siege on the Capitol that left five people dead, including a police officer.

Despite plans for more attacks, Trump has refused to walk back his false claims about election fraud, which inspired the January 6 mob to invade the building in an attempt to stop Congress from certifying President Biden’s election.

Instead, the former president has doubled down, falsely telling a receptive crowd at an event on February 28 that the 2020 election was "rigged" against him.