'Mystifying': AFP Photographer's Day Capturing US Capitol Rampage

The first thing that struck AFP photojournalist Saul Loeb as unusual when he arrived at the Capitol building to cover Joe Biden's election certification Wednesday was the thin police presence.

"It was basically like any other day on Capitol Hill for security. That was a bit surprising," recalled the 37-year-old, whose day was about to turn out unlike any other.

The photographer would go on to take defining images of an unprecedented breach of the halls of Congress, from a Trump supporter with his foot on a desk in top Democrat Nancy Pelosi's office to a marauding intruder wearing a fur hat with animal horns.

Loeb's working day had started relatively normally. He arrived early to set up, before taking his first pictures when the session started at 1:00 pm (1800 GMT).

It was when he was filing from the third floor that he heard a security announcement over the loudspeakers telling everyone not to move.

"Being a photographer, you hear something like that, you want to know what's going on," says Loeb, who has worked 14 years in Washington for AFP.

"So I went outside to find out what was going on. I heard some commotion, some shouting. There was a dozen or so protesters right outside the chamber.

"It is very rare to see even one protester in the Capitol itself, so to see a dozen right here, right outside the Senate door was highly unusual. At that point I thought, 'That was going to be the story of the day.'"

Loeb spends a few minutes taking photos as police try to convince the demonstrators to leave the building.

"They were mostly either ignoring us and letting us photograph them," says Loeb, taking up the story.

"We could get pretty close to them. Often they'd sort of encourage us to take a picture. They were in a jovial mood, they were happy to be there, somewhere they never expected to be."

Loeb sends those pictures and then explores what is happening elsewhere within the hallowed walls of American democracy, unaware at first that hundreds of protesters are inside.

"You could hear the chanting, the support for Trump and hundreds of protesters streaming into the Rotunda from seemingly every direction.

"Here is one of the most secure buildings in Washington, and it's completely filled with protesters," said Loeb, describing it as "mystifying."

"(They are) basically doing whatever they want, standing on benches, taking pics of the statues, just generally being loud and disruptive," he explains.

Loeb tries to make his way to the Senate Chamber, but can't -- police have blocked the hallway, the air thick with smoke, teargas and pepper spray.

He tries to go the lower House but encounters the same thing.

While contemplating where to go next, he sees protesters heading into the office of House Speaker Pelosi.

"It's a highly secure area, normally nobody can go into her office at all without an appointment and there is usually Capitol police standing outside."

Inside he sees rioters in "Make America Great Again" caps taking selfies, streaming themselves on social media, going through drawers and picking up mementoes.

"That's when I encountered one of the protesters sitting in a staffer's desk and putting his feet up, looking through her (Pelosi's) papers.

"That's the picture that a lot of people have seen now," he says, referring to his image of Richard Barnett, a pro-gun campaigner from Arkansas.

"He was happy to be photographed. He did not seem to be concerned at all that his face would be out there," recalls Loeb.

As Loeb left the building after an astonishing day, he was surprised to discover that, despite the breach and protesters roaming at will, the building "for the most part seemed relatively intact."