The FBI and Department of Homeland Security predict violent domestic extremists attacks will increase in 2021, according to a report reviewed by Axios.

Driving the news: The joint report says an unidentified group of extremists discussed plans to take control of the Capitol and "remove Democratic lawmakers" on or about March 4. The House canceled its plans for Thursday votes as word of the possible threats spread.

The big picture: The report lists government and law enforcement as possible targets by extremist groups who may exploit public gatherings to engage in violence.

• It says the groups are motivated byelection fraud and other conspiracy theories around the presidential transition.
• The report cited a QAnon conspiracy theory that former President Donald Trump will be inaugurated on March 4 — the date of the possible attack plans — or return to power on May 20 with the help of the U.S. military.
• It says extremist groups have also allegedly threatened to use explosives "to kill as many members as possible" during the upcoming State of the Union.
• The extremists were likely emboldened by the Jan. 6 Capitol building breach, according to the report.

Between the lines: Law enforcement is also warning about extremists turning to encrypted communications after mass purges from social media platforms after Jan. 6.

• Law enforcement's insight into threats is "increasingly constrained" by the use of secure communications by extremists, according to the report.

The bottom line: Capitol Police released a statement Wednesday morning acknowledging the increased threat to members and the Capitol grounds.

• "We have obtained intelligence that shows a possible plot to breach the Capitol by an identified militia group on Thursday, March 4," the statement reads.
• "We have already made significant security upgrades to include establishing a physical structure and increasing manpower to ensure the protection of Congress, the public and our police officers."