President Donald Trump has said he is not considering firing special counsel Robert Mueller even as his administration was again forced to grapple with the growing Russia probe that has shadowed the White House for much of his initial year in office.

Mr Trump returned to the White House from Camp David and was asked if he was considering triggering the process to dismiss Mr Mueller, who is investigating whether the president’s Republican campaign coordinated with Russian officials during last year’s election.

The president answered: “No, I’m not.”

But he did add to the growing conservative criticism of Mr Mueller’s move to gain access to thousands of emails sent and received by Mr Trump officials before the start of his administration, yielding attacks from transition lawyers and renewing chatter that Mr Trump may act to end the investigation.

“It’s not looking good. It’s quite sad to see that. My people were very upset about it,” Mr Trump said. “I can’t imagine there’s anything on them, frankly. Because, as we said, there’s no collusion. There’s no collusion whatsoever.”

On Saturday, the general counsel for the transition group sent a letter to two congressional committees arguing Mr Mueller’s investigators had improperly obtained thousands of transition records.

The investigators did not directly request the records from Mr Trump’s still-existing transition group, Mr Trump for America, and instead obtained them from the General Services Administration, a separate federal agency that stored the material, according to the group’s general counsel.

A spokesman for Mr Mueller said the records were obtained appropriately.

“When we have obtained emails in the course of our ongoing criminal investigation, we have secured either the account owner’s consent or appropriate criminal process,” Peter Carr said.

But many Trump allies used the email issue as another cudgel with which to bash the probe’s credibility. Members of the conservative media and some congressional Republicans have begun to systematically question Mr Mueller’s motives and credibility while the president himself called it a “disgrace” that some texts and emails from two FBI agents contained anti-Mr Trump rhetoric. One of those agents was on Mr Mueller’s team and has been removed.

Michael Caputo, a former Trump campaign aide, called the investigation an “attack on the presidency” and told CNN there are “more and more indications that the Mr Mueller investigation is off the rails”.

The talk of firing Mr Mueller has set off alarm bells among many Democrats, who warn it could trigger a constitutional crisis.

Some Republicans also advised against the move, including Senator John Cornyn of Texas, who deemed the idea “a mistake”.