An armed security contractor with three convictions for assault and battery shared an elevator with President Barack Obama in another embarrassing security lapse, it has emerged.
The incident took place at the Centers for Disease Control and Prevention in Atlanta on September 16, just days before an Army veteran carrying a knife managed to climb over the White House fence and sprint into the executive mansion.
The details of the earlier incident, which violated Secret Service protocol, came to light just hours after Secret Service Director Julia Pierson was questioned by Congress on Tuesday about the security breach at the White House.
The Atlanta incident, which was first reported by the Washington Post and the Washington Examiner, has been confirmed by a Secret Service spokesman.
The spokesman said there was an ongoing investigation into the episode.
The agency faced strong criticism from lawmakers yesterday for the incident at the White House.
The chairman of the House committee with oversight responsibilities for the Secret Service called for a a "top-to-bottom" review of the agency.
Republican Rep. Michael McCaul, the chairman of the House Homeland Security Committee, said: "I am deeply concerned with the lack of transparency from the Secret Service regarding the recent security breach at the White House.
"This latest episode adds to the growing list of failures from an agency plagued by operational challenges, cultural problems and reporting difficulties."
Pierson told the hearing she had briefed Obama only once this year - "for the September 19 incident."
She said shortly before alleged intruder, Omar J. Gonzalez, scaled the fence at least two of her uniformed officers recognized him from an earlier troubling encounter but did not approach him or report his presence to superiors.
She said Gonzalez was stopped on August 25 while carrying a small hatchet near the fence to the south of the White House.
Pierson told lawmakers the security plan at the White House was not "properly executed" in the September 19 incident when the intruder sprinted across the White House North Lawn and made his way into the mansion through an unlocked front door.
The hearing was told the intruder struggled with an officer inside the door before running past the staircase that leads to the residential quarters of the first family.
He was tackled by a Secret Service agent after making his way through the East Room.
An internal review is now underway to determine the full facts of the incident, Pierson told the hearing.
It has previously been reported the alleged intruder was arrested earlier in the summer in the nearby state of Virginia with weapons stashed in his car.
A federal prosecutor told a court last week that Gonzalez had a map on which the White House was circled.
The court heard that Gonzalez was under indictment for the Virginia incident, and was accused of possessing a sawn-off shotgun and trying to elude police.
Lawmakers on Tuesday also raised concerns about a 2011 incident which saw the Secret Service take four days to realise a man had fired a high-powered rifle at the White House. The incident was reported by the Washington Post on Sunday.
Gonzalez was due before federal court today, after he was indicted by a federal grand jury on Tuesday.
Additional reporting by Associated PressReuse content