WASHINGTON (Reuters)

White House deputy national security adviser Matt Pottinger has resigned, joining a number of officials who are leaving the administration of President Donald Trump following the storming of Capitol Hill by his supporters.

Pottinger, a leading figure in the development of Trump’s China policy, resigned on Wednesday in response to Trump’s reaction to a mob of protesters who breached the U.S. Capitol, a senior administration official told Reuters. Bloomberg first reported the resignation.

Pottinger’s boss, national security adviser Robert O’Brien, has no plans to quit, the official said.

“A strong national security team remains in place at the State Department, the Department of Defense, Treasury, the intelligence community and the National Security Council.”

The official said the team has been making sure there are no foreign threats to the United States prior to the incoming administration of President-elect Joe Biden, who will be inaugurated on January 20. The team has been coordinating with the Biden transition team for several weeks.

The White House had no immediate comment. O’Brien had asked Pottinger to stay on past election day to facilitate the transition to Biden’s new team, the official said.

“Pottinger completed those tasks,” the person said.

An administration official described Trump as “increasingly isolated” and said that “national security officials who are loyal to their oath to the constitution will be standing watch until Inauguration Day and will then turn over power to the duly elected new president.”

Four people died during the chaos – one from gunshot wounds and three from medical emergencies – after hundreds of Trump supporters stormed the Capitol in a bid to overturn his election defeat to Democrat Biden.

In a video posted to Twitter while the rioters roamed the Capitol, Trump called the protesters “special” and repeated his false claims about election fraud, although he urged protesters to leave.

The melee delayed the certification process of Biden’s victory for hours.

Two top aides to first lady Melania Trump also resigned on Wednesday. Stephanie Grisham resigned as chief of staff to the first lady.

“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, but a source familiar with her decision said it was the last straw.

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

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

Pottinger, a former Reuters and Wall Street Journal reporter who left journalism to join the U.S. Marines after the September 11 attacks on the United States in 2001, had served in the White House since the beginning of Trump’s presidency in 2017.

The departure of the fluent Mandarin speaker comes at a time of high tension with Beijing.

Trump’s administration has pursued hardline policies towards China on issues ranging from trade to espionage and the coronavirus and relations plummeted to their worst level in decades when the president ramped up rhetoric in his unsuccessful re-election campaign.

Early on Thursday, Secretary of State Mike Pompeo said Washington was considering sanctions and other restrictions on those involved in the arrest of over 50 people, including American lawyer John Clancey, in a new Chinese crackdown in Hong Kong hours before Wednesday’s events in Washington.

Pompeo warned that Washington could target Hong Kong’s economic and trade office in the United States, and in a move likely to further rile Beijing, announced that U.S. Ambassador to the United Nations Kelly Craft would visit Chinese-claimed Taiwan – which is not a U.N. member due to China’s objections.

U.S. lawmakers called the action by Trump’s supporters an embarrassment to American democracy that would play into the hands of rivals like China.

“I think they’re high-fiving in Beijing,” Republican Senator Marco Rubio, a China hawk, told Tucker Carlson on the Fox News channel. “It kind of bolsters their claim that we’re falling apart and they’re the country of the future.”

On Wednesday, China’s Washington embassy issued an advisory warning Chinese citizens to strengthen safety precautions in light of the “large-scale demonstration” in the U.S. capital and a curfew announced by the local government.