U.S. Democratic leaders have blasted FBI Director James Comey for refusing to join other top government officials in naming Russia as the hacking operation behind leaked Democratic e-mails in what one called a "blatant double standard."

Comey inserted himself into the political contest between Democratic presidential nominee Hillary Clinton and Republican Donald Trump last week by informing Congress that the FBI is investigating e-mails that surfaced during an investigation into former U.S. Representative Anthony Weiner, the estranged husband of a close Clinton aide.

But according to a report by CNBC on October 31, Comey refused to join a statement issued by the Department of Homeland Security and the Office of National Intelligence on October 7 attributing the leaking of hacked Democratic e-mails to Russia, arguing that it was too close to the election and he did not want to be seen as trying to influence the vote.

Clinton campaign manager Robby Mook said the revelation that Comey had reservations about naming Russia weeks before he announced an investigation into newly discovered e-mails shows "a blatant double standard."

The Senate's top Democrat, Harry Reid, accused Comey of having "a disturbing double standard for the treatment of sensitive information, with what appears to be a clear intent to aid one political party over another."

Reid charged that Comey violated a federal law that prohibits government employees from getting personally involved in elections or partisan politics.

“Your highly selective approach to publicizing information, along with your timing, was intended for the success or failure of a partisan candidate or political group,” Reid said in a letter to Comey.

Moreover, Reid charged Comey has been keeping under wraps "explosive information about close ties and coordination between Donald Trump, his top advisers, and the Russian government -- a foreign interest openly hostile to the United States, which Trump praises at every opportunity."

“I wrote to you months ago calling for this information to be released to the public...and yet, you continue to resist calls to inform the public of this critical information,” Reid said.

As Democratic leaders blasted Comey, Clinton continued her drumbeat of accusations about Trump's coziness with Russia, demanding that he fully disclose his ties with the Kremlin and "Russian oligarchs."

Since Comey announced the FBI's latest investigation, her support has declined significantly in opinion polls. While last week she was leading Trump nationwide by between 5 and 6 percentage points, by November 1 that lead had dwindled to 3.1 percentage points in an average of nationwide polls calculated by RealClearPolitics.com.

Trump now leads Clinton narrowly in two crucial battleground states -- Ohio and Florida -- that he must win to become president.

With reporting by AP, Reuters, CNBC, CBS News, and TASS