US President Donald Trump has deliver a blistering spray of insults at high-profile TV journalist who questioned him about Saturday’s shooting at White House Correspondents’ dinner.

Trump sat down with 60 Minutes journalist Norah O’Donnell on Sunday afternoon (US time), less than 24 hours after a man was arrested over the incident at the Washington Hilton.

His personal insults for O’Donnell, including calling her a “disgrace” and saying “you should be ashamed of yourself”, came after she read suspected gunman Cole Tomas Allen’s reported manifesto to Trump.

“The so-called manifesto is a stunning thing to read, Mr President. He appears to reference a motive in it. He writes this quote, ‘Administration officials, they are targets’,” O’Donnell said.

“He also wrote this, ‘I am no longer willing to permit a paedophile, rapist, and traitor to coat my hands with his crimes’.”

Trump interrupted O’Donnell to respond:

“I was waiting for you to read that because I knew you would because you’re horrible people. Horrible people,” he said.

“Yeah, he did write that. I’m — I’m not a rapist. I didn’t rape anybody. I’m not a paedophile. You read that crap from some sick person? I got associated with all — stuff that has nothing to do with me. I was totally exonerated.”

O’Donnell interjected: “Oh, do you think he was referring to you?”

Trump said 31-year-old Allen – who is in custody and is expected to face numerous charges when he initially faces court later on Monday – was “a sick person”.

“But you should be ashamed of yourself reading that because I’m not any of those things,”Trump told O’Donnell.

“You shouldn’t be reading that on 60 Minutes. You’re a disgrace. But go ahead. Let’s finish the interview.”

Allen, 31, a tutor and amateur video game developer, was arrested at the scene ‌of Saturday’s shooting in the Hilton ballroom.

Trump has said in TV interviews that he had posted an “anti-Christian” manifesto.

“He was a Christian, believer, and then he became an anti-Christian, and he had a lot of change,” Trump told CBS.

“He was probably a pretty sick guy.”

In a message to family members minutes before the attack, Allen described himself as “Friendly Federal Assassin” and railed against recent actions taken by the US government under Trump. He did not name the President directly.

Allen cited Christian theology as he said he was trying to protect those harmed by the administration’s policies.

“Turning the other cheek when *someone else* is oppressed is not Christian behaviour; it is complicity in the oppressor’s crimes,” the manifesto read, according to an official.

Targets listed in the manifesto included administration officials prioritised from highest-ranking to lowest, the official said.

The manifesto also mocked the “insane” lack of security at the Washington Hilton, where the dinner was held, the official said.

“Like, the one thing that I immediately noticed walking into the hotel is the sense of arrogance,” the manifesto’s author wrote.

“I walk in with multiple weapons and not a single person there considers the possibility that I could be a threat.”

Allen’s brother contacted police in New London, Connecticut, after receiving the writings, according to a law enforcement official. The police department confirmed the contact, which it said came about two hours after the shooting.

The chaotic events have raised fresh questions about the security of top US officials, many of whom were gathered in the hotel’s expansive ‌ballroom.

Trump has seized on the ‌attention to promote his ⁠planned White House ballroom as a safer venue for such events.

“This event would never have happened with the Militarily Top Secret Ballroom currently under construction at the White House. ​It cannot be built fast enough!” he wrote on Truth Social.

Allen checked into the Hilton on Friday, acting US Attorney General Todd Blanche said on multiple Sunday talk shows. Officials have said he allegedly fired a shotgun at a secret service agent at a security checkpoint in the hotel before being tackled and arrested.

Trump, first lady Melania Trump, Vice President JD Vance and cabinet officials were rushed out as Saturday night’s incident unfolded.

The secret service agent who was shot escaped serious injury because the bullet struck his protective vest, Trump ⁠said.

Blanche said Allen would face federal court on Monday charged with assault of a federal officer, discharging a firearm and attempting to kill a federal officer. More indictments are expected to follow.

A White House official said law enforcement officials who interviewed Allen’s sister were told he had a tendency to make radical statements, had attended an anti-Trump “No Kings” protest and referred to a plan to do “something” to fix global ​issues.

Trump suggested the protest might have spurred Allen to action.

“Part of the reason you have people like ​that is you have people doing No Kings,” he told CBS. “I’m not a king.”

-with AAP