FBI chief Comey was 'not up to the task': White House defends Trump

US President Donald Trump's decision to fire FBI Director James Comey has been supported by the White House, saying man who had been leading a probe into Russia's alleged meddling in November polls "was not up to the task".

The defence came after Trump in an interview to NBC had effectively contradicted his own White House when he said he would have sacked Comey "regardless" of the recommendation of Attorney General Jeff Sessions.

The White House had said Comey was fired "based on the clear recommendations of both Deputy Attorney General Rod Rosenstein and Attorney General Jeff Sessions." Later, Press Secretary Sean Spicer said the decision was the Justice Department's.

Trump's explanation, though, put him back in the position of power but had undermined the accounts of his senior staff.

Read more: Trump wanted to fire Comey from day one after losing faith in him: White House

The White House on Thursday attempted to clear the air on the several accounts leading to Comey's sacking that had been in the public domain. It said that Trump knew Comey was not upto the task so he decided to replace him with someone who could bring credibility back to the investigative agency.

"The president knew that Director Comey was not up to the task. He decided that he wasn't the right person in the job.

He wanted somebody that could bring credibility back to the FBI that had been lost over this last several months", White House Principal Deputy Secretary Sarah Huckabee Sanders said.

"The president made that decision. He made it. He moved forward. It was the right one", she told reporters responding to a volley of questions at her daily news conference.

An she repeated her assertion, "the only person that can fire Comey was the president. He made that decision."

"I think instead of getting so lost in the process, 'Did this happen at 12:01 or 12:02? Did he fire him because he wore a red tie or a blue tie?' he fired him because he was not fit to do the job. It's that simple", Sanders said.

She also defended the use of word "showboat" for Comey by Trump in an interview earlier in the day.

"I think that it speaks pretty clearly. Those words don't leave a lot of room for interpretation, so I think it's pretty clear what he meant", she said.

Read more: Donald Trump nominates Indian-American Neil Chatterjee for key position in FERC

Sanders reiterated that Trump lost confidence in Comey over the months. "After watching Director Comey's testimony last Wednesday, the president was strongly inclined to remove him", she said.

"On Monday, the president met with the attorney general and the deputy attorney general and they discussed reasons for removing the director. The next day, Tuesday May 9th, the Deputy Attorney General sent his written recommendation to the Attorney General, and the Attorney General sent his written recommendation to the President", Sanders said.

Those opposed to the sacking have claimed that Comey's 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.