Several Republican senators and representatives, including Liz Cheney and Mitch McConnell, are calling for the impeachment of President Donald Trump after the deadly riot at the US Capitol last week.
The shift within the Republican Party marks a change from years of support for Mr Trump and he is now being called on to resign after a mob of his supporters attacked the Capitol last Wednesday.
Mr Trump spoke to a rally of supporters before hundreds of them stormed the legislative building in Washington as Congress members were certifying president-elect Joe Biden's electoral victory.
Five people, including a US Capitol Police officer, died in the violence.
"I will vote to impeach the president," Ms Cheney, a representative from Wyoming, said in a statement on Tuesday night.
The House is presenting an article of impeachment on the floor on Wednesday, charging Mr Trump with "incitement of insurrection".
Ms Cheney's decision, as the third most powerful Republican in the House, made waves in political circles.
"Much more will become clear in coming days and weeks, but what we know now is enough," she wrote.
"The president of the United States summoned this mob, assembled the mob and lit the flame of this attack. Everything that followed was his doing.
"There has never been a greater betrayal by a president of the United States of his office and his oath to the constitution."
Mr Trump continues to stand by his inflammatory comments from last week and has not taken responsibility for influencing the mob's actions at the Capitol.
"What I said was totally appropriate," he said on Tuesday.
Two other Republicans announced that they will also vote for Mr Trump's impeachment.
John Katko was the first Republican House member to declare his support for holding the president accountable.
"To allow the president of the United States to incite this attack without consequence is a direct threat to the future of our democracy,” Mr Katko said.
“For that reason, I cannot sit by without taking action. I will vote to impeach this president."
Adam Kinzinger, a representative from Illinois, added to Republican support for impeachment.
"There is no doubt in my mind that the president of the United States broke his oath of office and incited this insurrection," Mr Kinzinger said.
"I must consider: if these actions … are not worthy of impeachment, then what is an impeachable offence?" Mr Kinzinger said. "I will vote in favour of impeachment."
Also making waves is a report in The New York Times that says Mr McConnell is happy that the House is moving on impeachment.
The report says the Senate majority leader from Kentucky believes Mr Trump has committed impeachable offences.
Mr McConnell is upset with the president over the violence at the Capitol, CNN reports, and believes impeachment would help the party to distance itself from Mr Trump and move on.
Mr McConnell has not definitively decided whether to vote for impeachment, reports said.
If impeachment passes the House, it will have to be sent to the Senate by majority leader Nancy Pelosi to fully impeach the president.
Seven Republican representatives have introduced a bill to censure Mr Trump for his role in encouraging the violence last week. Brian Fitzpatrick from Pennsylvania led the effort, releasing the three-page document on Tuesday night.
The resolution would censure and condemn the president for “trying to unlawfully overturn the 2020 presidential election and violating his oath of office on January 6, 2021”.
President Andrew Jackson in 1834 was the first and only US leader to be censured.