Story highlights "I believe the President's security was unnecessarily compromised," Chaffetz says

Secret Service official confirms to CNN reports of an incident when Obama visited the CDC

A private security contractor shared an elevator with the President, in violation of protocol

Secret Service director testifies she only briefed President on White House fence jumper

Testimony given by the director of the embattled U.S. Secret Service on Tuesday appears to conflict with the news that broke hours after Julia Pierson's testimony -- that a private security contractor with a gun shared an elevator with President Obama, in violation of protocol, during his trip to the Centers for Disease Control and Prevention in Atlanta two weeks ago.

In her testimony before the House Committee on Oversight and Government Reform , Pierson said she is responsible for briefing the President whenever there is a serious breach of his or his family's security. When asked how many times she had to take such action in 2014, she said it was only after the September 19 incident in which a man armed with a knife jumped the White House fence and made it into the mansion's East Room.

Not long after the hearing adjourned, the Washington Examiner and then the Washington Post reported the incident in Atlanta on September 16.

An agency official confirmed the incident to CNN in which a security contractor operating an elevator at the CDC was carrying a gun in the presence of Obama and his Secret Service detail. The contractor was taking pictures of the President and otherwise behaving in an unprofessional manner, the official said. When the security worker was confronted about his behavior, it was revealed that he was armed.

Asked about the apparent inconsistency in Pierson's testimony, a spokesman for the Secret Service, Ed Donovan, told CNN "we aren't going to discuss private conversations the director may have with the President."

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According to Secret Service protocols, it is up to the agency to decide who is allowed to possess firearms in the presence of the President. The agency official said that the elevator operator was determined not to be a threat to Obama after he was interviewed by officers.

White House officials did not respond to requests for comment from CNN.

"I believe the President's security was unnecessarily compromised," Rep. Jason Chaffetz, R-Utah, told CNN. "A convict with a gun in an elevator with the President put his life in danger. The Director should have informed the President, yet she testified she did not. Did she lie to Congress or fail to inform the President?"

Chaffetz at the hearing specifically asked Pierson "what percentage of the time do you inform the President that his personal security has in any way, shape or form been breached?"

"Percentage of the time?" Pierson responded. "A hundred percent of the time we would advise the President."

"You would advise the President," Chaffetz specified.

"Yes," she said.

"In calendar year 2014 how many times has that happened?" asked Chaffetz.

"I have not briefed him ... except for one occasion for the September 19 incident," she said, referring to the White House intruder who was able to breach White House security and get into the East Room of the White House.

Chaffetz clarified that the only time she had only briefed the President about his or his family's personal security in 2014 was the one time.

"That is correct," she said.

The elevator incident happened three days before the fence-jumping intrusion at the White House.