U.S. Transport Secretary Elaine Chao said Thursday she is resigning over the storming of the Capitol by President Donald Trump's supporters — the highest level White House resignation yet in the wake of the violence.
Ms. Chao, who is married to Republican Senate Majority Leader Mitch McConnell, said it was "a traumatic and entirely avoidable event as supporters of the president stormed the Capitol building following a rally he addressed."
"It has deeply troubled me in a way I simply cannot set aside," she added.
Several Democratic lawmakers dismissed the resignation as posturing. "Rats leaving a sinking ship," as Jackie Speier, a California congresswoman, said on Twitter.
But Ms. Chao was the most prominent in a group of about half a dozen officials to announce their departures from the Trump administration in less than 24 hours.
Earlier Thursday, former chief of staff Mick Mulvaney said he was quitting his diplomatic post to protest the mob violence, which Mr. Trump encouraged as he sought to overturn his election loss to Democrat Joe Biden.
"I can't stay here, not after yesterday. You can't look at that yesterday and think I want to be a part of that in any way, shape or form," Mr. Mulvaney told CNBC television .
Mr. Mulvaney, who had been serving as special envoy for Northern Ireland, said he informed Secretary of State Mike Pompeo of his resignation.
"I can't do it. I can't stay," he told CNBC , indicating that other White House staff were eying the exits.
"Those who choose to stay, and I have talked with some of them, are choosing to stay because they're worried the president might put someone worse in," he said.
Immediately after Wednesday's violence, which Mr. Trump has yet to condemn, deputy national security adviser Matt Pottinger resigned.
Another departure was Stephanie Grisham, a former White House press secretary now working as spokeswoman for First Lady Melania Trump.
U.S. media reported that Marc Short, Chief of Staff to Vice President Mike Pence, had been blocked from entering the White House — apparently in retaliation for Mr. Pence's decision to ignore Mr. Trump's demand that he block the certification of Mr. Biden's win.
In another sign of upheaval, Mr. Trump on Thursday withdrew his nomination of Chad Wolf for the permanent job at the head of the Department of Homeland Security, where he is now acting chief.
This came just after Mr. Wolf said he found the action by Mr. Trump's supporters in the halls of Congress "sickening" and urged the president to "strongly condemn" the violence.
The outrage across Washington at Wednesday's events is feeding growing speculation that more senior Trump administration figures may be leaving.
Particular focus has been put on Robert O'Brien, who holds the key post of national security advisor and has been reported to be considering resignation.
But Republican Senator Lindsey Graham, a heavyweight supporter of Mr. Trump during his tumultuous one-term presidency, begged top officials to stay put for the sake of stability.
"To those who believe you should leave your post now to make a statement, I would urge you not to," he said, urging O'Brien in particular to "stay on."
Mr. Biden will take over the Presidency when he is sworn in on January 20.