Illustration by Peter Sharkey.

A second small fence added as a supplement to the main fence is shown outside the White House on Pennsylvania Avenue. (Photo by Win McNamee/Getty Images)

During a House Oversight and Government Reform Committee hearing this morning, Secret Service director Julia Pierson took “full responsibility” for a recent security breach that allowed a knife-wielding man to jump the White House fence and enter the building.

A couple weeks ago, a knife-wielding Iraq war veteran jumped the White House fence, entered an unlocked door, and made it all the way to the East Room before being tackled by Secret Service. Initially, the Secret Service said that he was apprehended near the entrance, but the Post reported yesterday that the man actually made it to the East Room.

“It is clear that our security plan was not executed properly,’’ Pierson said in a statement before today’s hearing, the Post reports. “I take full responsibility. What happened is unacceptable and it will never happen again.”

The report released yesterday claims that after Omar Jose Gonzalez, who was allegedly carrying a knife, entered the White House, an alarm near the front entrance “had been muted at what officers believed was a request of the usher’s office.”

During the hearing, Pierson was reportedly grilled by members of the House Committee:

The bashing by lawmakers went beyond perceived failings in her management of the agency. Lawmakers interpreted her cool, measured responses as evasive and defensive.

“I wish to God you protected the White House like you’re protecting your reputation today,” said Rep. Stephen Lynch (D-Mass.).

Pierson replied that the Secret Service does not “take any of these incidents lightly.”

“I don’t think you’re taking it seriously,’’ Lynch answered.

He then added: “I’m sorry. I hate to be critical, but we have a lot at stake here. I got to call it like it is. I have very low confidence in the Secret Service under your leadership.”

Among the other things revealed during today’s committee hearing was that Gonzalez was tackled by an off-duty Secret Service agent who was on his way out the building when he spotted Gonzalez running in the East Room.

Pierson promised that changes to the Secret Service’s security plans are in the works to ensure this won’t happen again.

“There is no such thing as ‘business as usual’ in our line of work,” she reportedly said to the committee. “We have to be successful 100 percent of the time, and we are constantly making changes and doing everything possible to ensure that we are.”