Stephanie Grisham, the former White House communications director and press secretary and current chief of staff for first lady Melania Trump, submitted her resignation, effective immediately, in the wake of the violent protests, a White House official says.

White House social secretary Anna Cristina "Rickie" Niceta also resigned Wednesday effective immediately, a White House official told CNN.

Grisham and Niceta were among the longest-serving Trump administration officials.

Grisham began her tenure working for then-candidate Donald Trump in 2015 as a press wrangler on the campaign trail. She entered the White House as deputy press secretary under Sean Spicer, but in March 2017, Melania Trump hired her for her East Wing staff. As East Wing communications director, Grisham quickly became the first lady's most prominent staffer, acting as defender, enforcer and, often, protector.

"It has been an honor 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 told CNN in a statement.

The first lady's office did not immediately respond to CNN's request for comment.

Niceta served as the administration's sole social secretary, assuming the post in February 2017. The social secretary conducts and oversees all events at the White House, from small meetings in the West Wing to the annual Easter Egg Roll, Halloween, state visits, and congressional picnics and galas.

Niceta did not immediately respond to CNN's request for comment. 

White House press aide Sarah Matthews also resigned Wednesday night, saying in a statement that she was honoured to serve in the Trump administration, but "was deeply disturbed by what I saw today." She added, "Our nation needs a peaceful transfer of power." 

Meanwhile, several of Trump's top aides -- including national security adviser Robert O'Brien -- are considering resigning in the wake of his response to a pro-Trump mob breaching the US Capitol.

O'Brien, deputy national security adviser Matt Pottinger and deputy chief of staff Chris Liddell are all considering resigning, according to the sources. Pottinger's resignation appears to be imminent, while others could sleep on it. 

Earlier Wednesday, O'Brien took the unusual step of defending Vice President Mike Pence, as Trump has been consumed by the vice president's refusal to do his bidding instead of the mob that breached Capitol Hill. O'Brien said Pence showed courage as Trump lambasted him. 

"I just spoke with Vice President Pence. He is a genuinely fine and decent man. He exhibited courage today as he did at the Capitol on 9/11 as a Congressman. I am proud to serve with him," O'Brien said

O'Brien, Pottinger and Liddle did not immediately respond to requests for comment.

The President is being lambasted by his own party for his response to the day's events, including egging on his supporters and then justifying their riot in the US Capitol.

Earlier on Wednesday, Trump told a crowd of supporters gathered on the Ellipse near the White House that he planned to march with them to the Capitol building.

"We're going to walk down to the Capitol. And we're gonna cheer on our brave senators and congressmen and women. And we're probably not going to be cheering, so much for some of them, because you'll never take back our country with weakness, you have to show strength and you have to be strong," he said at his rally on the Ellipse.

Ultimately Trump skipped the march, returned to the White House in an armored SUV and hunkered indoors.