Federal prosecutors released a video on Thursday showing the moment an armed man tried to storm the White House Correspondents' Association dinner to allegedly attempt to kill US President Donald Trump.

The US attorney for Washington, Jeanine Pirro, posted the video on social media amid speculation that a Secret Service officer was struck by friendly fire as the suspect attempted to storm past agents.

"There is no evidence the shooting was the result of friendly fire," she wrote.

Prosecutors had previously claimed that the agent was shot in his bullet-resistant vest, but did not confirm if the bullet came from the suspect's gun. 

Trump, Pirro, Curran deny friendly fire

Secret Service ⁠Director ⁠Sean Curran claimed that the agent was shot at "point-blank range" by the suspect as he ran through a security checkpoint near the dinner.

"Our officer heroically returned fire," ​Curran said in an interview to Fox News, adding the agent fired five times.

Trump, too, denied that the agent was shot mistakenly by other officers. "They said it wasn't friendly fire. It wasn't us," he told reporters in the ​Oval Office on Thursday.

News agency Reuters, citing a US law enforcement official, reported that an investigation had been concluded the Secret Service agent was not hit by friendly fire.

What does the footage show?

The nearly six-minute video released by Pirro shows about a dozen federal officers taking down metal detectors at the security checkpoint and casually standing when the suspect appears to run through with a long gun in his hands. 

In the footage, the suspect appears to point his weapon at the said agent while running through. However, it was not immediately clear if the suspect fired a shot at that point.

The gunman had emerged from a doorway before he sprinted towards officers, most of whom did not notice him before he was nearly through.

Only one agent, who is said to have been shot by the suspect, had his weapon drawn before the armed man passed them.

The agent appears to shoot at the suspect at least three times in the video, though authorities say the gunman was not shot during the attack.

The footage also shows the suspect "casing the area" as he walked back and forth a hallway at the Washington Hilton hotel, a day before the gala dinner. He also briefly entered the hotel gym.

In the Fox News interview, Curran said there was only a 355-foot distance from the metal detectors to the podium where Trump was seated.

Suspect to remain in custody

The 31-year-old suspect was tackled and detained in a chaotic scuffle with security guards, which was not visible in the footage released on Thursday.

Earlier this week, he was charged with attempted assassination of the US president and faces life in prison if convicted.

The suspect on Thursday agreed to remain in custody while his case moves forward.

He would not immediately contest prosecutors' arguments that he was a danger to the community and ​should remain in jail, his attorney, Tezira Abe, said during a court hearing.

Edited by: Zac Crellin