WASHINGTON (AP) — Facing blistering criticism from Congress, Secret Service Director Julia Pierson said Tuesday she takes full responsibility for the breach of White House security in which a man with a knife entered the mansion and ran through half the ground floor before being subdued.

Pierson also said there have been six fence-jumpers this year alone, including one just eight days before Army veteran Omar J. Gonzalez jumped the fence on Sept. 11.

Pierson appeared Tuesday before the House Oversight and government Reform Committee.

“The fact is the system broke down,” declared committee chairman Darrell Issa.

Pierson was certain to face tough questions about why members of Congress briefed by the agency apparently weren’t told of the full extent of the breach when she appears before the House Oversight and Government Reform Committee.

Rep. Jason Chaffetz, R-Utah, said Monday night that whistleblowers told his committee that the intruder ran through the White House, into the East Room and near the doors to the Green Room before being apprehended. They also reported to lawmakers that accused intruder Omar J. Gonzalez made it past a female guard stationed inside the White House, Chaffetz said.

“I’m worried that over the last several years, security has gotten worse — not better,” Chaffetz said.

In the hours after the Sept. 19 fence-jumper incident, Secret Service spokesman Ed Donovan told The Associated Press that Gonzalez had been apprehended just inside the North Portico doors of the White House. The agency also said that night the Army veteran had been unarmed — an assertion that was revealed to be false the next day, when officials acknowledged Gonzalez had a knife with him when he was apprehended.

The Secret Service declined to comment on the latest details to trickle out of the investigation of the embarrassing security breach.

It was not clear late Monday what Homeland Security Secretary Jeh Johnson was told about the extent of the incident.

Senate Judiciary Committee staffers who were briefed about the investigation by the administration a week after the incident were never told how far Gonzalez made it into the building, according to a congressional official who wasn’t authorized to discuss the investigation and requested anonymity. The official said the committee later was told that the suspect had, indeed, made it far beyond the front door.

Chaffetz said his committee’s request for a briefing from the Secret Service on the incident was denied, a response he called “disappointing and frustrating.”

Asked whether he would seek an apology from Pierson, Chaffetz said, “We’re going to let things play out (Tuesday).”

Pierson’s predecessor, Mark J. Sullivan, apologized to lawmakers in 2012 after details emerged of a night of debauchery involving 13 Secret Service agents and officers in advance of the president’s arrival at a summit in Colombia. Sullivan retired about 10 months later.

Details of how far Gonzalez got into the White House were disclosed Monday.

Citing multiple unnamed sources, The Washington Post reported that Gonzalez ran past the guard at the front door, past a staircase leading up to the Obamas’ living quarters and into the East Room, which is about halfway across the first floor of the building. Gonzalez was eventually “tackled” by a counter-assault agent, the Post said.

Getting so far into the building would have required Gonzalez to dash through the main entrance hall, turn a corner, then run through the center hallway halfway across the first floor of the building, which spans 168 feet in total, according to the White House Historical Association.

Since the incident, the White House has treaded carefully. Although White House spokesman Josh Earnest acknowledged the president was “obviously concerned” about the intrusion, he expressed confidence in the Secret Service as recently as Monday.

It would be untenable for any president, not just Obama, to pointedly criticize the men and women who put themselves at risk to protect his life and family. That inherent conflict of interest means Congress, not the executive branch, is the most effective oversight authority for the Secret Service, its agents and officers.

“The president and the first lady, like all parents, are concerned about the safety of their children, but the president and first lady also have confidence in the men and women of the Secret Service to do a very important job,” Earnest said.