Mick Mulvaney, Donald Trump’s former chief of staff, has resigned as special US envoy to Northern Ireland and accused the President of "lighting the fuse" that led to riots at the US Capitol on Wednesday.
Mr Mulvaney told CNBC he rang Secretary of State Mike Pompeo on Wednesday night to tell him he "couldn't stay" in the post to which he was appointed in March.
The South Carolina politician visited Dublin, Belfast and London in September after his first trip as envoy was delayed due to the Covid pandemic. His role had been expected to end in 13 days time after Joe Biden takes office.
Speaking to the BBC on Thursday, Mr Mulvaney said he believed President Donald Trump had incited scenes anarchy during the disturbances in Washington DC in which four people died and 52 were arrested.
"I don't understand how you can interpret it any other way, when he gets to the crowd and says we're going to go down the street and do this, unless he was really believing they wouldn't take him seriously, that you could interpret it any other way," he said.
Mr Mulvaney described the riots as "an insurrection" that was "completely unacceptable" to most in the United States.
"I cannot tell you the number of people from both parties who have reached out to me this morning who are just in a stupor over what happened yesterday," he said.
However he disagreed with suggestions that such scenes were inevitable, saying even the strongest Trump opponents didn't believe such scenes were possible.
"This is something that was played up by fringe elements in the media, folks on the hardcore left-wing who said Donald Trump was the devil," he said.
"Donald Trump did not build the bomb that went off yesterday, he did not even build the fuse but he did light it.
"The fact that there was a bomb there and a fuse to be lit is something we need to struggle with as a nation.
"I never thought I'd see the day in my country where otherwise law-abiding citizens, that's what I assume those folks are, in fact I knew many people at the rally, they're from my home state of South Carolina, I saw them on the airplane going to Washington.
"We never thought we'd see the day that folks would do what they did in this riot yesterday. There is a lot of soul searching to be done," he added.
Mr Mulvaney said rhetoric used by Donald Trump since November, in which he claimed both the election and democracy had been stolen, is commonplace in the US.
"Rhetoric of that kind is used often in my country. No one ever acts on it," he said. "In a properly functioning United States of America, what happened yesterday would never happen."
President Trump's behaviour is not that of the President Mr Mulvaney knew, he claimed: "What we see now since the election is a different president and a different group of advisers. When he floats an idea that could be extreme, like X, they say "oh that's a great idea Mr President, we should do X plus three. It's not the A-team by any stretch of the imagination. It's a bizarre set of circumstances."
Donald Trump is unlikely is be impeached with less than two weeks left of his presidency but Mr Mulvaney believes he will attempt to pardon himself over any potential legal implications resulting from the events at the Capitol.
"The fact he put out a tweet overnight saying there would be a smooth transition leads me to believe cooler heads are prevailing in the West Wing today," Mr Mulvaney added.