The US Education Secretary, Betsy DeVos, became the second cabinet member to quit following the Capitol riot.

In her resignation letter, DeVos - one of the longest serving members of the president's administration - accused the president of fomenting Wednesday's disorder. "There is no mistaking the impact your rhetoric had on the situation, and it is the inflection point for me."

The transportation secretary had stepped down earlier. Elaine Chao said she had been "deeply troubled" by the rampage.

Other aides to quit include special envoy Mick Mulvaney, a senior national security official, and the chief of staff to First Lady Melania Trump. A state department adviser was also sacked after calling Trump "unfit for office" in a tweet.

But a Trump-supporting Republican strategist, Seth Weathers, played down the resignations, saying those quitting were never fully on board with Trump anyway.

"I think that these are people... were maybe not inclined to be Donald Trump-type individuals themselves, so I think it's understandable from their perspective, but I think unnecessary," he told the BBC.

"They stuck with Trump through all this time, why would they resign 13 days before he's leaving office anyway. It just seems rather pointless."