– James Comey, the director of the FBI, faced a dilemma Thursday when deputies briefed him about a new trove of e-mails, discovered in the course of an investigation of former Rep. Anthony Weiner, that they said might be connected to the dormant inquiry into Hillary Clinton’s private e-mail server.

Comey, who had cleared Clinton of any criminal wrongdoing in the e-mail affair this summer, could let Congress know about the new developments immediately, bureau officials said, an unusual step that would risk accusations that he was unfairly harming Clinton’s presidential campaign less than two weeks before the election.

Or he could delay any announcement and examine the new e-mails more closely, risking criticism that he had suppressed important new information if it came out after the election, despite his pledges of “transparency” in the investigation.

Comey, a Republican appointed by President Obama three years ago, decided that he could live with criticism of his judgment, aides said. So on Friday morning, the FBI’s congressional liaison e-mailed a letter from the director to the chairmen of eight congressional committees — virtually ensuring that it would be quickly publicized by eager Republicans.

The reaction was swift and damning, with Clinton’s supporters and even some Republicans blasting Comey. Indeed, Comey, who was attacked this summer by Democrats and Republicans for both his decision not to bring charges against Clinton and the way he handled it, found himself in an even stronger crossfire Friday.

By late Friday, Comey felt it necessary to further explain his actions in an e-mail to FBI employees in which he acknowledged that “there is significant risk of being misunderstood.” He explained that he was trying to balance the obligation he felt to tell Congress that the investigation he had said was completed was continuing, with not knowing yet “the significance of this newly discovered collection of e-mails.”

Across Pennsylvania Avenue from the FBI, Justice Department officials were said to be deeply upset about Comey’s decision to go to Congress with the new information before it had been adequately investigated.

That decision, said several officials who spoke on the condition of anonymity, appeared to contradict long-standing Justice Department guidelines discouraging any actions close to an election that could influence the outcome.

One official complained that no one at the FBI or the Justice Department is even certain yet whether any of the e-mails included national security material or was relevant to the investigation into whether Clinton had mishandled classified material in her use of a private e-mail server.

“The FBI has a history of extreme caution near Election Day so as not to influence the results,” Sen. Dianne Feinstein, D-Calif., said in a statement. “Today’s break from that tradition is appalling.”

“Was this information Congress needed to know urgently? Of course not,” said Matthew Miller, a Clinton supporter who was the chief spokesman at the Justice Department under former Attorney General Eric Holder.

Some Republicans praised Comey on Friday for his integrity and independence in coming forward with the new information. But praise was largely drowned out by criticism, with even some of Clinton’s biggest opponents upset at Comey’s sudden re-emergence in what they said was a bungled case.

“This is as bad for Comey as it is for Hillary,” said Tom Fitton, president of Judicial Watch, a conservative advocacy group that has successfully sued for access to thousands of Clinton’s private e-mails.

Fitton said the cryptic nature of Comey’s letter to Congress begged for an explanation as to what new material the FBI had found, whether it involved national security material relevant to the initial investigation and why it was not found earlier.

“This letter raises all sorts of questions that Comey and the FBI should have to answer,” Fitton said. “They can’t roll this out in the middle of a presidential campaign and just leave it at that.”

FBI officials said Comey was well aware that his decision would draw fire from many sides. Comey — who at 6-foot-8 is a dominating and charismatic figure — has not shied from the public spotlight and has shown an independent streak throughout his career.

As deputy attorney general in the George W. Bush administration, he butted heads with top White House officials for his refusal to sign on to a National Security Agency surveillance program. And he clashed with Obama and other administration officials last year over what he saw as a “Ferguson effect” discouraging the police from actively pursuing suspects.

A registered Republican for most of his adult life, Comey said in July that he is no longer registered with the GOP. He donated to the presidential campaigns of John McCain in 2008 and Mitt Romney in 2012.

Comey and his aides had hoped to put the Clinton e-mail controversy behind them this summer, when he decided — in unusually public fashion — not to seek criminal charges against Clinton or anyone else after a yearlong investigation.

But tensions have lingered, with Comey facing sharp second-guessing from Republicans on Capitol Hill and ongoing questions from even his allies.

The investigation of Clinton and her aides has been a major reason the bureau, more than at any time since at least the Watergate era, has been drawn uncomfortably into a presidential campaign.

FBI agents say their community meetings invariably lead to questions about what the bureau is or is not doing in connection with the election. Comey has urged his agents to stay above the fray. But many of them worry that regardless of the election’s outcome, the FBI might end up the loser.

“I’ve never seen it this bad,” said Robert E. Anderson Jr., who retired last year as the most senior agent overseeing criminal and cyber investigations. “I don’t know if it’s a low point for the bureau or the entire political process.”