An armed intruder said by prosecutors to have been a threat to the president made it much further into the White House after jumping a perimeter fence than the secret service first admitted, according to damning new evidence to be heard by a congressional panel on Tuesday.



Witnesses have told the House oversight committee that Omar Gonzalez overpowered an officer at the front door and was not stopped until he reached a separate room toward the back of the White House, according to testimony first reported by the Washington Post.



After running past a stairway leading to the first family’s living quarters, Gonzalez, a former army sniper, sprinted the 80-foot length of the East Room and was finally apprehended at the doorway to the Green Room – another formal room overlooking the South Lawn – the Post reports.



The account differs starkly from a press release issued by the secret service the day after the incident which merely says he was “physically apprehended after entering the White House North Portico doors”.



The impression that this meant he was stopped immediately after entering the doors is something administration officials did nothing to counter in the days after the event.



The ground-floor rooms of the main White House residence are normally highly guarded, as they are used for a range of public visits and guided tours, and the fact that Gonzalez was able to travel a considerable distance will compound concerns that the incident has revealed serious weaknesses in the protection given to Barack Obama and his family.



Utah Republican Jason Chaffetz, who chairs the House oversight subcommittee on homeland security, told CNN an alarm box near the front entrance had been muted, leaving interior personnel unaware of the intrusion before the suspect burst through the open front door, Reuters reported.

“I have deep concerns that the president is not as safe as we want and need him to be.”

Chaffetz said his information on the wild chase through the executive mansion came from whistleblowers interviewed during his congressional investigation into the incident.

Chaffetz is expected to seize on the alleged evidence from whistleblowers to demand an explanation of why the door through which Gonzalez entered the building was unlocked, as well as on suggestions that the alarm system had been muted because it had irritated ushers who worked at the door.



Obama and his family had left by helicopter from the South Lawn just minutes before Gonzalez, a former Iraq veteran allegedly carrying a pocket knife, scaled a fence outside the North Lawn and made it across the stretch of grass in front of the White House without being challenged by the snipers and dog patrols intended to guard against intruders.



Spokesmen for the secret service and the White House both declined to comment.

The White House earlier downplayed a separate Washington Post report into a shooting incident in 2011, which the Post says the secret service failed to properly investigate.



“As you would expect, the president and first lady, like all parents, are concerned about the safety of their children,” said spokesman Josh Earnest when asked about the Post’s reporting that Michelle Obama was furious about the attack, in which seven bullets struck the upstairs residence.



“But the president and first lady also have confidence in the men and women of the secret service to do a very important job, which is to protect the first family, to protect the White House, but also protect the ability of tourists and members of the public to conduct their business or even tour the White House.”



Gonzalez, who was allegedly found to have 800 rounds of ammunition and a machete in his nearby car, was described as “a danger to the president” by assistant US attorney David Mudd during a court hearing regarding the fence-jumping incident.

Chaffetz on Monday criticised the secret service for claiming it was exercising restraint by not shooting Gonzalez – who was originally reported to be unarmed – and argued there had been “epic failure from top to bottom” and that lethal force should be used stop to intruders entering the White House.