US Park Police stand along the sidewalk on Pennsylvania Ave. at a new layer of temporary fencing that appeared this week in front of the White House in Washington, in this file photo taken Sept 25, 2014. [Photo/Agencies]

WASHINGTON  - The man who breached security at the White House this month raced through several rooms on the main floor, penetrating farther into the building than previously disclosed, a Republican congressman said on Monday.

Representative Jason Chaffetz, who chairs a House subcommittee on national security oversight, 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.

"I have deep concerns that the president is not as safe as we want and need him to be," he said on CNN.

The suspect, Omar Gonzalez, 42, a decorated Iraqi war veteran, was charged with unlawfully entering a restricted building or grounds while carrying a deadly or dangerous weapon. Officials said he was carrying a knife when he jumped the White House fence and entered the executive mansion on Sept. 19.

The new details of the breach were first reported by the Washington Post on Monday on the eve of a hearing by the House Oversight and Government Reform Committee. They differ starkly from the Secret Service's statement the day after the incident that the suspect was "physically apprehended after entering the White House North Portico doors."

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

"The Secret Service has no comment on that at this time due to the ongoing investigation," Brian Leary, a spokesman for the agency, said of the Post story. A White House spokesman declined comment.

A prosecutor said in court last week that officers found more than 800 rounds of ammunition, two hatchets and a machete in Gonzalez' car.

Gonzalez had been arrested in July with a sniper rifle and a map on which the executive mansion was marked, the prosecutor said.

The Post said Gonzalez ran past a guard immediately inside the door, past the stairway leading up to the living quarters for President Barack Obama and his family and into the East Room, where he was tackled at the far end of the room by an agent.

The officer posted inside the door appeared to be delayed in learning the intruder was about to come through, the Post reported. Officers are trained to lock the front door immediately if they learn of an intruder on the grounds.

Secret Service Director Julia Pierson is expected to face questioning at a congressional committee hearing on Tuesday.