In a surprise show of comradeship, a number of Republicans have joined Democrats in attacking FBI chief James Comey for revealing his organisation is investigating newly uncovered emails associated with Hillary Clinton’s private server just 11 days before the presidential elections.

The Clinton campaign is currently working to contain damage from Mr Comey's announcement on Friday after the Democrat's lead dropped from 4.6 percentage points on Friday to 2.5 points on Monday, according to Real Clear Politics.

The FBI said it had found thousands of emails, during an unrelated investigation, which may be "pertinent" to its review of Ms Clinton's use of a private server from 2009 to 2013.

Mr Comey concluded in July that while Ms Clinton and her staff had been "extremely careless" in handling classified information, there were no grounds for any charges.

The announcement sparked intense backlash, with Clinton campaign manager Robby Mook calling the revelation a "blatant double standard" following a CNBC report that Mr Comey opposed releasing details about possible Russian interference in the US election because it was too close to election day.

Hillary Clinton email probe: Donald Trump hails decision to investigate new emails

Senator Harry Reid, the Democrat leader of the US Senate, accused the FBI of double standards in a letter sent to Mr Comey on Sunday, while Ms Clinton said the timing raised "a few questions" for the FBI, adding: “Voters deserve to get full and complete facts, so we call on director Comey to explain everything right away and put it all out on the table."

As criticism mounts against the FBI director, even Republicans have denounced the timing of the email revelation and a potential post-election spillover.

Ohio Republican congressman Jim Jordan, who chairs the House Freedom Caucus, told Fox News Radio: “I think this was probably not the right thing for Comey to do - the protocol here - to come out this close to an election, but this whole case has been mishandled, and now it is what it is."

In a letter addressed to Mr Comey on Monday, the Iowa Senator and head of the Senate Judiciary Committee Chuck Grassley called for more details about the revelation.

“I agree that your disclosure did not go far enough. Unfortunately, your letter failed to give Congress and the American people enough context to evaluate the significance or full meaning of this development,” wrote Mr Grassley.

“Without additional context, your disclosure is not fair to Congress, the American people, or Secretary Clinton.”

Newt Gingrich, a Trump campaign surrogate and former House speaker, said on Twitter: “We should not be forced to vote with ten thousand or more emails still hidden by the FBI. John Podesta [chairman of the Clinton campaign] and Hillary Clinton are right."

In an op-ed for the New York Times, chief ethics lawyer in the Bush White House Richard Painter wrote: "I never thought that the FBI could be dragged into a political circus surrounding one of its investigations. Until this week.”

Joe Walsh, a Trump supporter and former Republican congressman, has posted a series of tweets slamming the timing of Mr Comey’s decision. His remarks include: “What he just did 11 days [before] the election is wrong and unfair to Hillary.

"I want Trump to win, but what Comey just did to Hillary Is wrong & really unfair to her."

Larry Thompson, a Bush deputy attorney-general, wrote in an op-ed in The Washington Post co-authored with Jamie Gorelick: "We now have ... a kind of reality TV of federal criminal investigation ... it is antithetical to the interests of justice, putting a thumb on the scale of this election and damaging our democracy."

Jeanine Pirro, a former GOP prosecutor, judge and Trump supporter, said on Fox News that Mr Comey's actions "disgraces and politicises" the FBI.

The Justice Department, moving to address concerns over the timing of the revelation of the emails and a potential post-election spillover, said it would "dedicate all necessary resources" to concluding the review promptly.

At the White House, spokesman Josh Earnest said he would neither defend nor criticise the timing of Mr Comey's disclosure. But he also said President Barack Obama did not believe Mr Comey was trying to influence the election, or attempting to benefit one candidate or party.