A government official told The Associated Press that the Justice Department had advised the FBI against telling Congress about new developments in the Hillary Clinton email investigation because of the potential fallout so close to the election.
The FBI said it recently came upon new emails possibly pertinent to that investigation.
Director James Comey said in a letter to Congress that the FBI discovered the emails while pursuing an unrelated case and would review whether they were classified.
The government official said the Justice Department concluded the letter would be inconsistent with department policy that directs against investigative actions that could be seen as affecting an election or helping a particular candidate.
The official said Comey made the decision to go ahead with the letter independently of the Justice Department, that he felt "an obligation" to send the letter.
The official wasn't authorized to discuss the department's internal deliberations publicly and spoke on condition of anonymity.
Meantime, Clinton's campaign has lashed out at the FBI.
The campaign said there's no indication that a cache of recently discovered emails being reviewed by the agency is even about her.
Clinton campaign chairman John Podesta said FBI Director James Comey's information is "long on innuendo'' and "short on facts.''
He added there's "no evidence of wrongdoing. No charge of wrongdoing. No indication this is even about Hillary.''