The head of the House Oversight Committee said Friday that there may be allegations of "quid pro quo" between a top aide to Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE and an FBI official detailed in newly released documents from the bureau's investigation of Clinton's private email server from her time as secretary of State.

Rep. Jason Chaffetz Jason ChaffetzThe myth of the conservative bestseller Elijah Cummings, Democratic chairman and powerful Trump critic, dies at 68 House Oversight panel demands DeVos turn over personal email records MORE (R-Utah) has not reviewed the documents released Friday, he told Fox News, but based on briefings he said "there was an alleged quid pro quo” between State Department Undersecretary for Management Patrick Kennedy and an FBI official over a classified email.

“In return for altering the classification, the possibility of additional slots for the FBI at missions overseas was discussed,” Chaffetz said.

He said he was "infuriated" by the news and said there are grounds for at least four congressional hearings on the issue.

The FBI disputed Chaffetz's characterization, saying the two subjects came up in the same conversation but were unrelated.

"The FBI determined that one such email was classified at the Secret level. A senior State Department official requested the FBI re-review that email to determine whether it was in fact classified or whether it might be protected from release under a different FOIA exemption," the bureau said in a statement to Fox News.

"A now-retired FBI official, who was not part of the subsequent Clinton investigation, told the State Department official that they would look into the matter. Having been previously unsuccessful in attempts to speak with the senior State official, during the same conversation, the FBI official asked the State Department official if they would address a pending, unaddressed FBI request for space for additional FBI employees assigned abroad," it added.

The FBI said that the classification of the email was not changed.

"Although there was never a quid pro quo, these allegations were nonetheless referred to the appropriate officials for review," the statement read.

Chaffetz said: "Left to their own devices the FBI would never have provided these [records] to Congress and waited until the last minute. This is the third batch because [the FBI] didn’t think they were relevant."

Fox News previously reported that elsewhere in the FBI's notes from its investigation into Clinton's server, an unnamed employee from the Office of Information Programs and Services (IPS) accused Kennedy of pressuring subordinates to alter classification codes on Clinton's emails to skirt Freedom of Information Act rules.

"This is a flashing red light of potential criminality," said Chaffetz.