US President Donald Trump was rushed to a White House bunker on Friday by Secret Service agents as hundreds of people protesting the death of George Floyd gathered outside the executive mansion, some of them throwing rocks and tugging at police barricades.

Mr Trump spent nearly an hour in the bunker, which was designed for use in emergencies like terrorist attacks, according to a Republican close to the White House who was not authorised to publicly discuss it and spoke on condition of anonymity.

READ MORE:  George Floyd death: US endures another night of violent protests

The source’s account was confirmed by an administration official who also spoke on condition of anonymity.

The abrupt decision by the agents underscored the rattled mood inside the White House, where the chants from protesters in Lafayette Park could be heard all weekend and Secret Service agents and law enforcement officers struggled to contain the crowds.

America Protests WashingtonDemonstrators in Washington are protesting the death of George Floyd in police custody (Alex Brandon/AP)

Friday’s protests were triggered by the death of Mr Floyd, a black man who died after he was pinned at the neck by a white Minneapolis police officer.

The demonstrations in Washington turned violent and appeared to catch officers by surprise, sparking one of the highest alerts on the White House complex since the September 11 attacks in 2001 .

“The White House does not comment on security protocols and decisions,” said White House spokesman Judd Deere, while the Secret Service said it does not discuss the means and methods of its protective operations.

The president and his family have been shaken by the size and venom of the crowds, according to the Republican source who spoke with the Associated Press.

America Protests WashingtonGeorge Floyd died after being restrained by Minneapolis police officers (Alex Brandon/AP)

It was not immediately clear if First Lady Melania Trump and the couple’s 14-year-old son, Barron, joined the president in the bunker, though Secret Service protocol would have called for all those under the agency’s protection to be in the underground shelter.

Mr Trump traveled to Florida on Saturday to view the first manned space launch from the US in nearly a decade. He returned to a White House under virtual siege, with protesters — some violent — gathered just a few hundred yards away through much of the night.

READ MORE:  George Floyd: US police officer arrested after death in custody

Demonstrators returned Sunday afternoon, facing off against police at Lafayette Park into the evening.

America Protests MinneapolisProtests have continued around the country including in Minneapolis, where Mr Floyd died (John Minchillo/AP)

As cities burned night after night and images of violence dominated television coverage, Mr Trump’s advisers discussed the prospect of an Oval Office address in an attempt to ease tensions.

But the notion was quickly scrapped for lack of policy proposals and the president’s own seeming disinterest in delivering a message of unity.

In recent days security at the White House has been reinforced by the National Guard and additional personnel from the Secret Service and the US Park Police.

On Sunday, the Justice Department deployed members of the US Marshals Service and agents from the Drug Enforcement Administration to supplement National Guard troops outside the White House, according to a senior Justice Department official who spoke anonymously.