Ex-FBI director James Comey will testify that Donald Trump sought his "loyalty" as he makes his eagerly anticipated first comments in public since being fired by the US president.

The former director is set to lift the lid on several politically sensitive meetings and phone calls he had with Mr Trump when he gives testimony to Congress on Thursday.

Mr Comey had been overseeing the federal investigation into possible ties between Mr Trump's campaign and Russia's election meddling when he was sensationally dismissed on May 9.

Among the key evidence, revealed across seven pages of prepared remarks, Mr Comey will claim:

The planned testimony before the Senate intelligence committee appears to show Mr Trump's disregard for the FBI's traditional independence from the White House.

Mr Comey's unease with the Republican president is made clear in several passages.

He states the discussion over "loyalty" came during a dinner at the White House on January 27.

Mr Comey says he replied that he could offer the president his honesty, to which Mr Trump replied that he wanted "honest loyalty".

Mr Comey said he paused and said: "You will get that from me."

The former director also describes at length a meeting in the Oval Office on February 14 in which he believed Mr Trump asked him to the probe into Mr Flynn's links with the Russian ambassador.

Mr Comey claims Trump said: "I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go."

He said he "replied only that 'he is a good guy'."

The testimony comes as the US president confirmed former Justice Department official Chris Wray will be his pick to replace Mr Comey as FBI head.