Trump says Russia probe head acted honourably, but warns of retaliation

Trump, who feels vindicated by the dropping of collusion allegations, said he would favor publication of the wider Mueller report. So far, only a short summary has been released.

"Up to the attorney general. Wouldn't bother me at all," he said at the White House.

But Trump blasted the investigation as "a false narrative, it was a terrible thing."

"We can never let this happen to another president again," he said. "Very few people I know could have handled it. We can never, ever let this happen to another president again."

Adding to suggestions that the White House would like to retaliate now that the damaging investigation is over, Trump said "there are people out there who have done very bad things, I would say treasonous things against our country."

"We've gone through a period of really bad things happening -- those people will certainly be looked at," he said.