James Comey. Alex Wong/Getty Images FBI Director James Comey argued in private against accusing Russia of meddling in the US election, contending it was too close to election day in November for such an announcement, a former FBI official told CNBC on Monday.

That allegation came just days after Comey sent a letter to congressional leaders informing them that the FBI found new emails in another investigation that may be "pertinent" to the investigation into Hillary Clinton's use of a private email server, which he had deemed closed over the summer.

The Friday announcement regarding Clinton came just 11 days before the election, well within the department's standard of not releasing information that could affect a presidential or congressional election within 60 days of voting. Comey's now facing a barrage of attacks from prominent Democrats and political analysts for sending the shocking letter on Friday.

The unidentified CNBC source said that Comey made sure his organization's name was not on the document released by the US government, cited repeatedly by Clinton and her campaign but denounced by Republican nominee Donald Trump, that evidence pointed to Russia meddling in the US election.

That source added that insiders were puzzled why Comey would have issues with the timing regarding the Russia disclosure, but not with the email discovery, which reportedly were uncovered in connection with an investigation into disgraced Rep. Anthony Weiner — who's estranged wife, Huma Abedin, is a top Clinton aide — over allegations he sexted with a 15-year-old girl.

A representative for the FBI declined a request for comment from Business Insider.

Without the FBI's involvement, the Department of Homeland Security and the Office of the Director of National Intelligence issued an early October statement saying the "US intelligence community is confident that the Russian Government directed the recent compromises of emails from US persons and institutions, including from US political organizations ... These thefts and disclosures are intended to interfere with the US election process."

The former official said that Comey agreed with the conclusion that other prominent US intelligence sources came to.

"A foreign power was trying to undermine the election," the source said. "He believed it to be true, but was against putting it out before the election ... if it is said, it shouldn't come from the FBI, which as you'll recall it did not."

The source said Comey had a different approach to the email revelation because of his summer press conference on his determination. In July, Comey announced that the case had reached its conclusion and he would not recommend charges, later saying no prosecutor would. He did, however, say Clinton acted with "extreme carelessness" in using the private server.

"By doing a press conference, and personally testifying and giving his opinion about the conduct, he made this about James Comey and his credibility," the official said. "You can see why he did it, from his perspective, once he had had that press conference."

A Sunday Wall Street Journal report indicated that there could be as many as 650,000 emails to sift through, and it's unknown how many are potentially related to Clinton. Other reports showed Comey apparently went against the recommendation of the Department of Justice in sending the letter to congressional leaders.

The CNBC report was almost immediately blasted out by prominent Democrats, including Clinton herself on Twitter, who posted the story with the caption "incredible."

Senate Minority Leader Harry Reid's office joined in as well.

His deputy chief of staff, Adam Jentleson, sent the story out to his press list with the caption "Ahem."

In a scathing Sunday night statement, Reid may have foreshadowed today's story, contending that Comey had demonstrated a double-standard, making the explosive claim that he withheld information about Trump's possible ties to Russia.

"In my communications with you and other top officials in the national security community, it has become clear that you possess explosive information about close ties and coordination between Donald Trump, his top advisors, and the Russian government — a foreign interest openly hostile to the United States, which Trump praises at every opportunity," Reid said. "The public has a right to know this information."

"I wrote to you months ago calling for this information to be released to the public," he continued. "There is no danger to American interests from releasing it. And yet, you continue to resist calls to inform the public of this critical information. By contrast, as soon as you came into possession of the slightest innuendo related to Secretary Clinton, you rushed to publicize it in the most negative light possible."

But it is worth noting that the CNBC story came from just a single source. In mid-October, a similar single-source story was published in Fox News, claiming that the career agents and attorneys working the Clinton case "unanimously" believed Clinton should have been charged. The FBI is notorious for internal strife between offices and individuals attempting to grab power and tear down others, and there's a chance that, in both cases, a source was looking to sting Comey.

Asked about promoting the one-source story, Clinton's campaign manager Robby Mook told reporters in a conference call that the story had been confirmed by a Huffington Post story, which relied on an anonymous non-FBI source.

"We're simply acting on the information we have here, which has now been confirmed by two sources," he said after slamming House Republicans for calling the letter from Comey a "re-opening" of the case based on what he deemed as minimal information.

Clinton's campaign also called on Comey to release all information on FBI investigations into Trump and his associates ties to Russia.

"Director Comey is the one who opened this door," Mook said, later adding, "It was Director Comey who opened this door and broke protocol."