Trump allies turn on special counsel Robert Mueller

The comments come amid increasing frustration at the White House and among Trump supporters that the investigation will overshadow the president's agenda for months to come - a prospect that has Democrats salivating.

Mr Trump cannot directly dismiss Mr Mueller. That decision would fall to Deputy Attorney General Rod Rosenstein, who said on Tuesday in a Senate budget hearing that he would only fire Mr Mueller for good cause and has seen no evidence of that.

Still, Chris Ruddy, the CEO of Newsmax and a friend of Mr Trump, suggested the president was already thinking about "terminating" Mr Mueller from his position as special counsel.

"I think he's weighing that option," Mr Ruddy said in an interview on Monday with Judy Woodruff of PBS NewsHour.

House Speaker Paul Ryan told reporters that any talk about Mr Trump wanting to rid himself of the special investigator amounts to rumour.

But it is a line of thinking that is making its way to the president's ears.

Former House speaker Newt Gingrich said that Mr Trump called him on Monday night because of Mr Gingrich's concerns about the Russia probe.

He called because "I have been very clear" about Mr Mueller and the lawyers he has hired amounting to a "rigged game," Mr Gingrich said in an interview with news channel CBS.

"It's a mistake to pretend that this is going to be some neutral investigation," he said.

Even so, Mr Gingrich said, Mr Trump will not seek to dismiss Mr Mueller because he is confident the probe will conclude he has done nothing wrong.

Mr Rosenstein is charged with Mr Mueller's fate because Attorney General Jeff Sessions recused himself from all matters having to do with the Trump-Russia investigation.

Mr Sessions made that choice because of his own conversations with Russian officials during the Trump transition - a potential part of the probe.

Representative Adam Schiff, the top Democrat on the House Intelligence committee, said any move to oust Mr Mueller would "be the last straw" for many in Congress and would have "echoes of Watergate," when president Richard Nixon dismissed special prosecutor Archibald Cox over Mr Cox's subpoenas for White House tapes.

Mr Schiff told news channel MSNBC's Morning Joe programme on Tuesday that "I don't think the Congress would sit still and allow the president to pick his own investigator".

Just weeks ago, Mr Gingrich had heaped praise on Mr Mueller, hailing him as a "superb choice" for special counsel whose reputation was "impeccable for honesty and integrity."

But after the evidence of former FBI director James Comey last week, Mr Gingrich said he had changed his mind. Mr Gingrich said he is troubled by Democratic donations of Mr Mueller's picks to help lead the probe.

Conservative commentator Ann Coulter offered a similar message, tweeting: "Now that we know TRUMP IS NOT UNDER INVESTIGATION, Sessions should take it back & fire Mueller."

The new talk about dismissing Mr Mueller appeared to be coming from Trump allies - including some close to White House strategist Steve Bannon - who are increasingly frustrated with the prospect of a long and winding probe.

They say Mr Trump did not collude with Russia and see the investigation as a politically motivated sham that handicaps Mr Trump's ability to execute his agenda, according to one person who advises the White House on how to handle the probe.

Mr Ruddy appeared to be basing his remarks, at least in part, on comments from Jay Sekulow, a member of Mr Trump's legal team, who told ABC in an interview on Sunday that he was "not going to speculate" on whether Mr Trump might at some point order Mr Rosenstein to fire Mr Mueller.

"Look, the president of the United States, as we all know, is a unitary executive. But the president is going to seek the advice of his counsel and inside the government as well as outside. And I'm not going to speculate on what he will or will not do," Mr Sekulow said.

"I can't imagine that that issue is going to arise," he added.

It was not clear whether Mr Ruddy, who speaks with the president often, was basing his remarks on a specific conversation with the president or entirely on Mr Sekulow's comments.

Mr Ruddy was at the White House on Monday to meet with White House aides, but did not speak with the president, Press Secretary Sean Spicer said.

"Mr Ruddy never spoke to the president regarding this issue," Mr Spicer said. "With respect to this subject, only the president or his attorneys are authorised to comment."

White House spokeswoman Sarah Huckabee Sanders said: "Chris speaks for himself."

Peter Carr, a spokesman for Mr Mueller, declined to comment on Mr Ruddy's remarks.

AP