WASHINGTON — FBI official Brian McCauley had been trying for weeks to get his contact at the State Department to approve his request to put two bureau employees back in Baghdad.

Around May 2015, Patrick Kennedy finally called back.

“He said, ‘Brian. Pat Kennedy. I need a favor,’ ” McCauley recalled in an interview Tuesday. “I said, ‘Good, I need a favor. I need our people back in Baghdad.”

Then Kennedy, a longtime State Department official, explained what he wanted in return: “There’s an email. I don’t believe it has to be classified.”

The email was from Hillary Clinton’s private server, and Kennedy wanted the FBI to change its determination that it contained classified information. McCauley and others ultimately rejected the request, but the interaction – which McCauley said lasted just minutes over maybe two conversations – has become the latest focal point of the bitter 2016 presidential campaign. The Democratic candidate’s critics have suggested that the conversation between the State Department and the FBI demonstrated inappropriate collusion to benefit Clinton.

In an hour-long interview with The Washington Post, his first public comments on the matter, McCauley acknowledged that he offered to do a favor in exchange for another favor, but before he had any inkling of what Kennedy wanted. The FBI and the State Department have denied that McCauley and Kennedy ever engaged in a “quid pro quo.”

McCauley, who has since retired from the FBI, said he asked Kennedy to send him the email in question and then inquired with another bureau official about it because he had only a partial understanding of the request. McCauley said that when he learned the missive concerned the attack on the U.S. consulate in Benghazi, Libya, he told Kennedy he could not help him.

“I said, ‘Absolutely not, I can’t help you,’ and he took that, and it was fine,” said McCauley, who was the FBI’s deputy assistant director for international operations from 2012 to 2015.

In a statement released by the State Department, Kennedy said he reached out because he wanted “to better understand a proposal the FBI had made to upgrade one of former Secretary Clinton’s emails prior to its public release,” and that McCauley raised the topic of FBI slots in Iraq “as an entirely separate matter.” He said he could not speak to McCauley’s recollection but insisted: “There was no quid pro quo, nor was there any bargaining. At no point in our conversation was I under the impression we were bargaining.”

Kennedy also said in the statement his motivations “were never political.”

“I have served as a member of the Foreign Service for some 40 years – serving both Democratic and Republican administrations,” Kennedy said. “My sole aim was to ensure that we were responsive to our legal obligations under FOIA.”

The FBI and the State Department have said the bureau did not get the personnel in Iraq it was seeking, and the State Department ultimately did not persuade the FBI to change its position that the email be classified as secret.

The purported “quid pro quo” between McCauley and Kennedy was first reported over the weekend by the Weekly Standard and confirmed Monday when the FBI released dozens of interview summaries from its criminal investigation into Clinton’s use of a private email server while she was secretary of state.

The interview summaries showed that Kennedy lobbied multiple bureau officials to change their minds about classifying one email on Clinton’s server. At the time, the State Department was reviewing Clinton’s emails for release under the Freedom of Information Act, and had sent several to the FBI for review.

The bureau determined one of them contained classified information. The determination came before the FBI had launched its criminal investigation into whether Clinton and her aides had mishandled classified information, though it was nonetheless significant. If the bureau and other agencies had found no classified material on Clinton’s private server, she probably would have avoided the criminal investigation altogether.

There is no evidence that Clinton knew about Kennedy’s and McCauley’s discussion, and McCauley said Kennedy never even invoked Clinton’s name. In March 2015, Clinton said there was no classified information on her private server.

Agents investigating Clinton’s use of a private server would ultimately interview McCauley, and said in their summary of that conversation that McCauley told Kennedy he would “look into the email matter if Kennedy would provide authority concerning the FBI’s request to increase its personnel in Iraq.”

McCauley said in an interview that when he agreed to look into the matter, he “was just being kind and polite.” And he said “there was no contingency” binding his looking into the email classification to Kennedy’s agreeing to approve his request for FBI personnel in Iraq.

“He had a request. I found out what the request was for. I absolutely said emphatically I would not support it,” McCauley said.

But one of his colleagues at the FBI’s records division told investigators that McCauley relayed his conversation with Kennedy in a way that suggested Kennedy had offered a “quid pro quo,” according to a summary of that official’s interview. McCauley disputed that characterization.

“That’s a reach,” McCauley said. “I said, ‘Hey, what is this about?’ ”

Kennedy would eventually press the FBI records official and others to change the classification of the email, absent any deal, the records official alleged. In one meeting of government agencies, when someone asked whether any emails were classified, the records official told investigators that Kennedy remarked, “Well, we’ll see,” and spent 15 minutes afterward debating the classification of a message.

Kennedy said in his statement that he believed the email should have been redacted but not because it was classified.

“We take very seriously our responsibility to decide whether our documents are classified or not classified,” he said. “We can’t simply cede that responsibility to another agency, as it is my signature or one of my senior officers’ signature which goes on the classification action and it is the State Department which must prepare the legal justification if we are challenged in court.”

The State Department and Clinton allies have sought to cast disagreement over what should be classified and what should not as routine. Brian Fallon, a Clinton campaign spokesman, said in a statement: “It is well known that there was strong disagreement among various government agencies about the decisions to retroactively classify certain material in emails sent to Secretary Clinton. Agencies that took issue with this overclassification did so based on their own beliefs, and we were not part of these disagreements that played out inside the government.”

McCauley said Kennedy never pressured him and that he was unaware of Kennedy’s conversations with others. McCauley said he worked with Kennedy fairly often when the bureau needed to move personnel overseas for investigations, and he speculated that their prior relationship was why Kennedy reached out to him.

McCauley said, though, he had no authority to actually change classification.

“We got along, and I was always going to him,” McCauley said. “I was a regular name, regular face. Maybe he thought I was in a position where I could support him? One, I wasn’t, and two, I wouldn’t.”

U.S. Rep. Jason Chaffetz, R-Utah, chair of the House Oversight Committee, called the interaction “stunning.” He said while it was particularly troublesome that Kennedy had pressed to change the FBI’s classification decision, the bureau was “not clean in this either.”

“The fact that they’re even having this discussion is potentially a violation of law,” Chaffetz said. “I do give the FBI credit for ultimately saying no, but why were they talking to these people? It’s because Patrick Kennedy knew that they wanted something from the State Department.”

Chaffetz said his committee planned to push the FBI to release more documents related to the Clinton probe and that it would also consider issuing subpoenas to witnesses.

Republican presidential candidate Donald Trump said in a video statement that the episode was an example of “collusion between the FBI, Department of Justice and the State Department, to try and make Hillary Clinton look like an innocent person, when she’s guilty of very high crimes.”

Retired Lt. Gen. Michael Flynn, a Trump supporter whom McCauley said he considers a friend, issued a statement saying the FBI’s interview summaries “provide undeniable proof that Hillary Clinton colluded with the FBI, DOJ and State Department to cover up criminal activity at the highest levels.”

McCauley said that was his friend’s “opinion” and “when something is said like that, there has to be proof.”

“Listen, there was no collusion, there was absolutely no collusion,” McCauley said. “That’s illegal. Something that was underhanded, illegal, I would not do it. No one in the FBI would do it. It’s a matter of integrity.”

McCauley said he was never disciplined for the exchange nor interviewed by the FBI’s Office of Professional Responsibility or the Justice Department’s inspector general. He said he left the bureau for health reasons in the summer of 2015. He was not a part of the criminal Clinton email investigation.