The insurrectionist mob who stormed the US Capitol last week was overwhelmingly made up of supporters of US president Donald Trump, including Republican Party officials and donors, far-right militants, white supremacists and members of the military, an investigation shows.

They came from across America, summoned by Mr Trump to march on Washington in support of his false claim that the November election was stolen and to stop the congressional certification of Democrat Joe Biden as the victor.

The president had tweeted a week before Christmas: "Big protest in D.C. on January 6th. Be there, will be wild!"

Some members of the mob were adherents of the QAnon conspiracy myth that the US government is secretly controlled by a cabal of Satan-worshiping paedophile cannibals.

Records show that some were heavily armed and included convicted criminals, such as a Florida man recently released from prison for attempted murder.

The Associated Press reviewed social media posts, voter registrations, court files and other public records for more than 120 people either facing criminal charges related to the January 6 unrest or who, going maskless amid the pandemic, were later identified through photographs and videos taken during the mayhem.

The evidence gives lie to claims by right-wing pundits and Republican officials such as representative Matt Gaetz that the violence was perpetrated by left-wing "antifa" thugs, rather than supporters of the president.

"If the reports are true," Mr Gaetz said on the floor of the US house of representatives just hours after the attack, "some of the people who breached the Capitol today were not Trump supporters. They were masquerading as Trump supporters and, in fact, were members of the violent terrorist group antifa."

Steven D'Antuono, the assistant director in charge of the FBI's Washington field office, told reporters that investigators had seen "no indication" antifa activists were disguised as Trump supporters in Wednesday's riot.

The AP found that many of the rioters had taken to social media after the November election to retweet and parrot false claims by Mr Trump that the vote had been stolen in a vast international conspiracy.

Several had openly threatened violence against Democrats and Republicans they considered insufficiently loyal to the president.

During the riot, some livestreamed and posted photos of themselves at the Capitol. Afterwards, many bragged about what they had done.

As the mob smashed through doors and windows to invade the Capitol, a loud chant went up calling for the hanging of vice president Mike Pence, the recent target of a Trump Twitter tirade for not subverting the US constitution and overturning the legitimate vote tally.

Outside, a wooden scaffold had been erected on the National Mall, a rope noose dangling at the ready.

So far, at least 90 people have been arrested on charges ranging from curfew violations to assaults on police officers, possessing illegal weapons and making death threats against US house speaker Nancy Pelosi.

Among them was Lonnie Leroy Coffman, 70, an Alabama grandfather who drove to Washington to attend Mr Trump's "Save America Rally" in a red GMC Sierra pickup packed with an M4 assault rifle, multiple loaded magazines, three handguns and 11 Mason jars filled with homemade napalm, according to court filings.

Also facing federal charges is Cleveland Grover Meredith Jr, a Georgia man who in the wake of the election had protested outside the home of Republican governor Brian Kemp, whom Mr Trump had publicly blamed for his loss in the state.

Meredith drove to Washington last week for the "Save America" rally but arrived late because of a problem with the lights on his trailer, according to court filings that include expletive-laden texts in which he allegedly stated he was "thinking about" shooting Ms Pelosi in the head on live TV.

Federal law enforcement officials vowed to bring additional charges against those who carried out the attack on the Capitol, launching a nationwide manhunt for dozens of suspects identified from photographic evidence

The FBI has opened a murder probe into the death of Capitol police officer Brian D Sicknick, who was hit in the head with a fire extinguisher.

The four Trump supporters who died in the riot were Kevin D Greeson, 55, of Athens, Alabama; Benjamin Philips, 50, of Ringtown, Pennsylvania; Ashli Babbitt, 35, of San Diego; and Rosanne Boyland, 34, of Kennesaw, Georgia.

The AP's review found that QAnon beliefs were common among those who heeded Mr Trump's call to come to Washington.

Doug Jensen, 41, was arrested by the FBI on Friday in Des Moines, Iowa, after returning home from the riot. An AP photographer captured images of him confronting Capitol Police officers outside the senate chamber on Wednesday.

Jensen was wearing a black T-shirt emblazoned with a large Q and the phrase "Trust The Plan", a reference to QAnon.

Jake Chansley, who calls himself the "QAnon Shaman" and has long been a fixture at Trump rallies, surrendered to the FBI field office in Phoenix on Saturday.

News photos show him at the riot shirtless, with his face painted and wearing a fur hat with horns, carrying a US flag attached to a wooden pole topped with a spear.

The FBI identified Chansley by his distinctive tattoos, which include bricks circling his biceps in an apparent reference to Mr Trump's border wall.

There were also current and former members of the US military in the crowd, including US army Captain Emily Rainey, a 30-year-old psychological operations officer. She told the AP she led 100 members of Moore County Citizens for Freedom who travelled to Washington to "stand against election fraud" and support Mr Trump.

Capt Rainey insisted she acted within army regulations and that no-one in her group entered the Capitol or broke the law.

Derrick Evans, a Republican recently sworn in as a delegate to the West Virginia house, resigned on Saturday following his arrest on two charges related to the Capitol riot after streaming video of himself charging into the building with the mob.