[WASHINGTON] Fired FBI director James Comey withheld judgment Thursday on whether President Donald Trump requests that he drop an investigation into his former national security advisor amounted to obstruction of justice.

"I don't think it's for me to say whether the conversation I had with the president was an effort to obstruct. I took it as a very disturbing thing, very concerning," he said, speaking before the Senate Intelligence Committee in a hearing broadcast live around the world.

"But that's a conclusion I'm sure the special counsel will work towards to find out the intention and whether that's an offense," he added, referring to the independent prosecutor placed in charge of the FBI's Russia probe.

Despite Mr Trump's request that he drop the probe into former national security advisor Michael Flynn Russia ties, Mr Comey said no one in the administration ever asked him to drop the FBI's overall investigation into whether anyone in the Trump campaign collaborated with a Russian bid to interfere in the 2016 election.

Asked specifically if Mr Trump made such a request, Mr Comey replied: "Not to my understanding, no". But he said he took "as direction" the president's words on the Flynn probe when he said "I hope you can let it go".

"He's the president of the United States, with me alone, saying 'I hope this' - I took it as this is what he wants me to do."

AFP