Former US president, Donald Trump has called for FBI Director Christopher Wray to resign after the bureau chief cast doubt on claims Trump was struck by a bullet during the attempt on his life at a Pennsylvania political rally despite the world seeing the attack live as it happened.

Christopher Wray was updating Congress about the assassination attempt on Trump in Butler on Wednesday, July 24 when he made the explosive statement.

'With respect to former President Trump, there’s some question about whether or not it’s a bullet or shrapnel that hit his ear,' Wray said.

'I don't know right now whether that bullet, in addition to causing the grazing, could have landed somewhere else.'

Trump calls for FBI director to resign after he casted doubt on whether the former president was struck by bullet during ass@ssination attempt at rally

Wray was talking about security failures that allowed gunman Thomas Matthew Crooks to open fire. Crooks, 20, killed firefighter Corey Comperatore, 50, and injured two others including Trump during the shooting.

Trump has since given extensive accounts of the moment he was shot and was seen wearing a bandage over his ear.

Trump calls for FBI director to resign after he casted doubt on whether the former president was struck by bullet during ass@ssination attempt at rally

Trump calls for FBI director to resign after he casted doubt on whether the former president was struck by bullet during ass@ssination attempt at rally

'When I went down, bullets were coming over my head and you hear them, it's like a zip, zip,' he said.

Trump said his Secret Service detail 'thought it was over when I went down' because of 'a lot of blood coming' after his ear was grazed.

Trump, 78, argued with his agents, telling them how he was 'not going on a stretcher' and instead vowed to 'get up'.

He added that a last-minute turn of the head to glance at a screen is what saved him from the bullet.

'I'm supposed to be dead. The most incredible thing was that I happened to not only turn but to turn at the exact right time and in just the right amount,' he added, saying he survived 'by luck or by God'.

Some initial reports on the day of the shooting speculated that Trump may have been struck by a shattered piece of glass when a bullet struck the teleprompter.

The teleprompter theory, however, was debunked when photos showed that both glass screens were not damaged after the attack.

The investigation has thrust the bureau into a political storm, with conspiracy theorists alleging it was an inside plot to get rid of Trump ahead of the election.

Questions about the shooting dominated the session, but Wray was asked if he had personally observed any cognitive decline in meetings with Biden prior to his decision to withdraw from the election.

His answer that he had not witnessed any issues with the president's mental state left Trump unimpressed, with the Republican nominee calling for Wray to resign.

'I watched the Congressional Hearing today as Christopher Wray was asked the question whether or not he noticed any Cognitive Degeneration in his many conversations with Crooked Joe Biden,' Trump wrote on Truth Social Wednesday.

'Wray should resign immediately from the FBI, and stop 'sweet talking' Congress every time he goes up, which he loves to do, because anybody can see that Joe Biden is cognitively and physically challenged.

'And if you can't see that, you sure as hell can't be running the FBI - Unless, that is, you want to illegally lead the Raid on Mar-a-Lago. Wray has to resign, and NOW, for LYING TO CONGRESS!'