Updated

Transportation Secretary Elaine Chao announced Thursday that she is stepping down from her post, a day after the rioting on Capitol Hill -- making her the latest member of the Trump administration to resign over the president's conduct, and the first Cabinet member to do so.

"Yesterday, our country experienced a traumatic and entirely avoidable event as supporters of the President stormed the Capitol building following a rally he addressed," she said in a letter to the department. She said her resignation would take effect on Monday.

CAPITOL RIOTS SPUR MULVANEY, GRISHAM, OTHER TRUMP ADMINISTRATION OFFICIALS TO RESIGN 

"As I'm sure is the case with many of you, it has deeply troubled me in a way that I simply cannot set aside."

Chao's resignation comes amid a tidal wave of criticism of President Trump over his conduct related to a pro-Trump protest that stormed the Capitol building shortly after a rally featuring the president was held outside the White House. The assault on the Capitol came as lawmakers were voting to certify the Electoral College results -- something that Trump had called on Vice President Mike Pence to reject. The vice president presided over the vote in a joint session of Congress. 

Four people died, including one person who was shot to death, and at least 62 were arrested amid the chaos that saw lawmakers evacuated and the certification delayed. Lawmakers later returned to certify the Electoral College vote.

Chao has served in the administration since 2017 and is one of the longest-serving Cabinet members. She is also married to Senate Majority Leader Mitch McConnell, R-Ky., who has refused to back President Trump’s election challenges.

In her statement, she said she was "tremendously proud" of the accomplishments during her tenure. She also pledged that the department would help Pete Buttigieg -- President-elect Joe Biden's pick to lead the department when he is inaugurated.

Andy Post, Chao's former head of communications, told Fox News that she "was arguably the most successful and qualified member of the Cabinet during this administration."

"She effectively managed many challenging situations in transportation over four years, especially in aviation, and will be remembered for her steady leadership," he said.

Chao is one of a number of Trump administration officials to step down -- although so far she is the only Cabinet member to do so.

White House Deputy Press Secretary Sarah Matthews, East Wing Chief of Staff Stephanie Grisham and Social Secretary Rickie Niceta all submitted their resignations.

Late Thursday morning, a senior administration official told Fox News that Matt Pottinger, deputy national security adviser, resigned Wednesday afternoon as a result of the president’s actions and the attack on the U.S. Capitol. 

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Mick Mulvaney -- special envoy to Northern Ireland and Trump's former chief of staff -- on Thursday also resigned, telling CNBC: "I can’t stay here."

Meanwhile, acting Homeland Security Secretary Chad Wolf called on Trump to "strongly condemn" what he described as "unconscionable" violence in a statement released earlier Thursday.

Less than two hours after the statement was posted, the White House announced that Trump had withdrawn Wolf's name to become the permanent secretary of DHS -- although the White House said the withdrawal had been made on Wednesday and was "not related at all to Wednesday’s events or the Acting Secretary’s comments this morning."

The FBI is asking for help identifying individuals who may have been involved in violent conduct or rioting. Anyone with information is asked to call 1-800-CALL-FBI or visit http://fbi.gov/USCapitol.