Stephanie Grisham resigned as chief of staff to the first lady after supporters of President Donald Trump violently occupied the US Capitol on Wednesday in an effort to block Congress from certifying the presidential election results.

"It has been an honour to serve the country in the White House. I am very proud to have been a part of Mrs Trump's mission to help children everywhere, and proud of the many accomplishments of this administration," Grisham said in a statement.

Grisham, who spent a year as White House press secretary before becoming chief of staff to the first lady, did not say whether her resignation was in reaction to the violence in the nation's capital, but a source familiar with her decision said the violence was the last straw for her.

The White House social secretary, Rickie Niceta, also resigned, as did a deputy White House press secretary, Sarah Matthews, two sources told Reuters.

O'Brien was also considering resigning, as was Pottinger, the deputy national security adviser who has been a key voice on China policy within the administration, two sources said.

"I just spoke with Vice President Pence," O'Brien said in a statement earlier Wednesday, adding, "I am proud to serve with him."

There was also chatter inside the White House that deputy chief of staff Chris Liddell might resign, a source said.

The White House declined to comment.

Multiple injuries were reported and one woman was killed in the melee at the Capitol, as Trump supporters responded to the president's call to protest his loss in November's presidential election to Democrat Joe Biden.

Trump has repeatedly and baselessly claimed the election was marred by fraudulent voting.

Australian Associated Press