A gunman burst out of a hotel doorway and charged through a security checkpoint in just four seconds as President Donald Trump was attending a press gala, according to new footage released by prosecutors.

The CCTV video appears to show a security agent opening fire in the direction of the sprinting gunman, who is carrying a long-barrelled weapon, though it is unclear if he discharges it.

The clip does not show the moment where investigators say the alleged attacker fell over and was arrested at the Washington Hilton on Saturday.

Cole Tomas Allen, 31, is charged with attempting to assassinate President Trump at the White House Correspondents' Association dinner. He has not yet entered a plea.

The US justice department says the video also shows Allen "casing the area" at the hotel on the day before the dinner, when he allegedly checked in as a guest.

He is seen walking down a Washington Hilton corridor on the eve of the gala and popping into the hotel's gym, according to prosecutors.

The defendant is accused of carrying a semi-automatic handgun, a pump-action shotgun and three knives as he ran through a terrace level, one floor above the basement ballroom where the high-profile press gala was unfolding.

Trump, Vice-President JD Vance, cabinet members and other White House officials were rushed from the venue after gunfire rang out.

The new video, posted on X on Thursday by US Attorney for Washington DC Jeanine Pirro, appears to be a higher quality version of a clip shared by Trump on social media in the aftermath of Saturday's incident.

The latest footage shows nearly a dozen security agents gathered around a security checkpoint at the hotel.

A man wearing a long dark coat walks through the corridor and disappears into a doorway.

A moment later the gunman, having shed his coat, re-emerges and sprints through a metal-detector with both hands on what appears to be a gun.

His coat was concealing a 12-gauge shotgun, according to an affidavit filed by prosecutors.

The footage appears to show an officer fire his handgun at the suspect. Prosecutors have said the agent was hit by gunfire, but the alleged assailant was not shot.

A Secret Service spokesman told the BBC on Thursday: "The officer was struck in the ballistic vest, but was not seriously injured."

Ballistics experts have been investigating whether the Secret Service officer was hit by a bullet fired by the suspect, or by other law enforcement at the scene.

Pirro said in Thursday's post on X: "There is no evidence the shooting was the result of friendly fire."

However, a memo filed by prosecutors on Wednesday, asking a judge to hold Allen in custody pending trial, makes no mention of any officer being shot.

It says that as the suspect ran through the checkpoint, a Secret Service officer "observed the defendant fire the shotgun in the direction of the stairs leading down to the ballroom".

Earlier statements in charging documents alleged that one officer was hit in the ballistic vest by a single shot fired by the suspect.

Defence lawyers for Allen have questioned prosecutors' claims that their client opened fire.

On Thursday the director of the US Secret Service told Fox News that the suspect had fired at a Secret Service agent at "point-blank range".

"All the evidence that I've seen, the suspect shot our officer point-blank range with a shotgun," Sean Curran told the network.

"Our officer heroically returned fire while being shot point-blank range in the chest with a shotgun, he was able to get off five shots.

"It appears that the suspect hit his knee, while being engaged by the officer, on one of our magnetometer boxes and began to fall to the ground.

"That's what appears to be, and at that moment is when officers and agents were able to subdue him and pile on top of him."

Allen faces additional charges, including transportation of a firearm between states to commit a felony and discharging a firearm in a crime of violence - both of which have maximum sentences of 10 years.