Former Attorney General William Barr and a growing number of Republicans, former supporters of President Donald Trump, are condemning the president’s incitement of the violent mob that stormed the US Capitol on January 7.

Trump’s conduct was a “betrayal of his office” Barr said in a statement to The Associated Press news agency on Thursday.

Members of Trump’s Cabinet and some political allies have discussed his removal under emergency provisions of the US Constitution, the Reuters news agency reported, citing a source familiar with the situation.

Democratic politicians in the US Congress and one Republican are now openly calling for Trump’s immediate removal or resignation with just 13 days until President-elect Joe Biden is to be inaugurated.

Barr, who had resigned as the top US law enforcement official at the end of 2020, said “orchestrating a mob to pressure Congress is inexcusable”.

Barr was one of President Trump’s most loyal and ardent defenders in the Cabinet.

His comments came a day after angry and armed protesters broke into the US Capitol, forcing members of Congress to halt proceedings to certify Biden’s election and retreat from the House and Senate chambers.

Barr had resigned in December amid tension with Trump over Barr’s refusal to back the president’s baseless claims of election fraud and initiated an investigation into Biden’s son Hunter Biden.

He joins a growing chorus of Republican former allies of Trump who are now blaming him for inciting the insurrection at the Capitol.

Former White House Chief of Staff Mick Mulvaney, who has been serving as US ambassador to Northern Ireland, said he was resigning.

“It’s a small job,” Mulvaney said, but “you can’t do it” after what happened on Wednesday.

Former White House Chief of Staff Mick Mulvaney attends as US President Donald Trump hosts a lunch for ambassadors to the UN Security Council at the White House in Washington, DC, US December 5, 2019 [Jonathan Ernst/Reuters]

“I would not be surprised to see more of my friends resign over the course of the next 24 hours,” Mulvaney said in a CNBC television interview on Thursday morning.

Mulvaney said some other Trump officials are appalled by the president’s actions but are choosing to stay out of concern they would be replaced by Trump loyalists who would “make things even worse”.

Mulvaney praised Vice President Mike Pence for breaking with Trump to preside over Congress’s certification of Democrat Joe Biden’s election victory.

Mulvaney is a former Republican congressman who as Trump’s White House chief of staff had publicly defended Trump in his 2019 impeachment by the House of Representatives.

Representative Adam Kinzinger, a Republican, who had also defended Trump but has been increasingly critical of Trump’s false claims about the election, joined calls by Democrats for removal of the president.

“It’s with a heavy heart I am calling for the sake of our democracy that the 25th Amendment be invoked,” Kinzinger said on Twitter.

The 25th Amendment of the US Constitution provides for replacement of a president by the vice president by a vote of two-thirds of the Cabinet officers.

“The president is unfit. And the president is unwell,” Kinzinger said. Trump “must now relinquish control of the executive branch voluntarily or involuntarily”.

In Senate remarks on Wednesday night after order was restored to the Capitol, South Carolina Republican Senator Lindsey Graham said Trump’s ride as president is over.

“Trump and I, we’ve had a hell of a journey,” said Graham, who like Barr has been one of Trump’s most vocal supporters.

“Count me out, enough is enough, I’ve tried to be helpful,” Graham said.

Democrats in Congress including Senate leader Chuck Schumer are formally calling on Pence and Trump’s Cabinet members to invoke the 25th Amendment now.

“What happened at the US Capitol yesterday was an insurrection against the US, incited by the president. This president should not hold office one day longer,” Schumer said in a statement issued by his office on Thursday.

Former House Speaker John Boehner said it is time for the Republican Party to recognise Trump’s lies and incitement.

“I once said the party of Lincoln and Reagan is off taking a nap. The nap has become a nightmare for our nation. The GOP must awaken,” Boehner said in a tweet.