US House Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer urged Vice President Mike Pence to invoke a provision in the Constitution to remove President Donald Trump from office after his supporters ransacked the Capitol.
“I join the Senate Democratic leader in calling on the vice president to remove this president by immediately invoking the 25th Amendment,” Ms Pelosi said on Thursday.
“If the vice president and Cabinet do not act, the Congress may be prepared to move forward with impeachment.”
The 25th Amendment of the US Constitution allows the vice president and a majority of the presidential Cabinet to remove the president from office if he is “unable to discharge the powers and duties of his office".
But if the president objects, two thirds of Congress must vote to remove him or he will remain in office.
Most congressional Republicans have refrained from holding Mr Trump responsible for the mob that stormed the Capitol building on Wednesday, temporarily disrupting the formal certification of president-elect Joe Biden's victory.
Should Ms Pelosi follow through on her threats to impeach Mr Trump for the second time in his term, the Democrat-held House would have to vote on articles of impeachment as it did in 2018.
It would then fall to the Senate to conduct a trial and vote on removing the president from office.
The impeachment process is long and Mr Trump has only 13 days left in office.
The Senate has adjourned until January 19 and the House is not scheduled to meet until Mr Biden’s inauguration on January 20.