In an interview, Trump says he always planned to fire FBI Director Comey

US President Donald Trump insisted Thursday he always intended to fire FBI director James Comey, undercutting the initial White House explanation that he acted on the recommendation of top justice officials.

Opponents have claimed that Comey's shock sacking was a bid to stall an FBI investigation into alleged Russian meddling in the 2016 election, which is also looking into possible collusion between the Kremlin and Trump's team.

In announcing Comey's dismissal on Tuesday, the White House said it was based on a damning assessment of his handling of a probe into Hillary Clinton's emails — but Trump told the NBC network that he was always going to dismiss him.

"I was going to fire him regardless of recommendations," said the president. "He's a showboat, he's a grandstander." 

Vice President Mike Pence and a string of White House officials have said Trump acted upon the advice of Attorney General Jeff Sessions and his deputy, Rod Rosenstein — although administration officials have also said the president had steadily "lost confidence" in Comey's leadership prior to firing him.

Trump's interview was released on the same day the interim head of the FBI told the US Congress that Comey's sacking would not derail the Russia investigation.

"There has been no effort to impede our investigation to date," acting director Andrew McCabe told the Senate Intelligence Committee, in a hearing that capped two days of high drama provoked by the dismissal.

"You cannot stop the men and women of the FBI from doing the right thing," he said. "All of the agents involved in the investigation are still in their positions."

While Trump told NBC that the outgoing director had left the agency in "turmoil", McCabe rejected any suggestion that Comey had lost the support of the Federal Bureau of Investigation's rank and file.

"Director Comey enjoyed broad support within the FBI and still does today," he told the committee. "I hold director Comey in the highest regard. I have the highest respect for his abilities and his integrity."

Echoing a widely-held view in opposition ranks, the senior democrat on the Senate committee, John Warner, called the timing of Comey's dismissal "especially troubling."

"He was leading an active counterintelligence investigation into any links between the Trump campaign and the Russian government or its representatives, and whether there was any coordination between the campaign and Russia's efforts to interfere in our election." 

"For many people, including myself, it is hard to avoid the conclusion that the president's decision to remove Director Comey was related to this investigation."

McCabe gave no information on the status of the FBI probe, which dates back to July last year when the agency became aware of alleged Russian hacking of Democratic party computers and communications.

'Not under investigation'

McCabe and five other top intelligence officials, including the heads of the Central Intelligence Agency and the National Security Agency, reiterated their January conclusion that the Russian government was behind the effort to manipulate last year's election.

Trump has repeatedly downplayed suspicions of Russian interference, and dismisses any notion of collusion with his team as "fake news."

The president told NBC he had personally asked Comey whether he was under investigation — an admission that could expose the president to allegations of interfering with the ongoing FBI probe.

"I actually asked him, yes. I said, 'If it's possible would you let me know am I under investigation?'" Trump said, recounting one of three conversations about the issue — two over the phone and one over dinner.

"He said, 'you are not under investigation,'" Trump claimed, repeating an assertion he first made as he announced Comey's firing.

McCabe refused to respond to panel questions on the claim, saying: "I can't comment on any conversations the director may have had with the president."

He also pledged not to discuss the Russia investigation with the White House, saying it had adequate resources to proceed. Unconfirmed media reports said that Comey in recent weeks sought more financial resources from the government to support the probe.

"I can assure you we are covered," McCabe told the panel when asked if the FBI needs more money for the investigation.