Underneath the White House there's a secret bunker. On Friday, Donald Trump retreated to it.

On Friday night as protests in the US rage for a fourth night and started to inch closer and closer to the White House, President Donald Trump retreated to a secure presidential bunker which hadn’t been used since the days after 9/11.

The demonstrations were sparked by the death of 46-year-old black man George Floyd who died at the hands of police last Monday.

A video shows white police officer Derek Chauvin pushing down on Floyd’s neck with his knee as the unarmed man breathlessly repeats: “I can’t breathe.”

Watch: Donald Trump has addressed the country after the seventh night of protests. Post continues after video.

Hundreds gathered outside Trump’s executive mansion, some of them throwing rocks and tugging at police barricades.

According to reports, the mood in the White House was “rattled” and the chants of protestors could be heard through the halls.

Late on Friday evening, Secret Service officers abruptly moved the president underground, The New York Times reports.

He spent about an hour in the ‘bunker’, designed for use in emergencies such as terrorist attacks. It’s not known whether first lady Melania Trump and the couple’s 14-year-old son, Barron, joined him.

After his evening underground, Trump emerged on Saturday morning to boast on Twitter: “I was inside, watched every move, and couldn’t have felt more safe.”

Great job last night at the White House by the U.S. @SecretService. They were not only totally professional, but very cool. I was inside, watched every move, and couldn’t have felt more safe. They let the “protesters” scream & rant as much as they wanted, but whenever someone….

— Donald J. Trump (@realDonaldTrump) May 30, 2020

His response to the Black Lives Matter protests which continue to spread across his country – and now the world – have been drawing strong criticism, with his tweets laced with racist rhetoric.

Overnight he reportedly labelled the country’s governors “a bunch of jerks” telling a video conference: “You’ve got to arrest people, you have to track people, you have to put them in jail for 10 years and you’ll never see this stuff again.”

Inside the secret bunker. 

There is so much more to the White House than meets the eye.

Buried deep beneath the western side of the lawn, The Drive reports there is an “extravagant and modern complex,” which is made up of a labyrinth of passageways and rooms.

It dates back to World War II, but was updated between 1948 and 1952, when the White House was gutted and rebuilt.

Called the “President’s Emergency Operations Center”, or PEOC, its makeover included updating it to survive an atomic weapon attack.

Photographs taken inside the PEOC on September 11, 2001, during the New York terror attack on the World Trade Centre, were released to the public after a Freedom of Information request by Frontline.

In 2010 it was reportedly upgraded again by the Obama administration, as part of an AUD $551 million construction project that was referred to officially as "an air conditioning and mechanical systems upgrade".