WASHINGTON (AP) — Secret Service Director Julia Pierson vows that a security breach like the Sept. 19 incident in which a man scaled the White House fence and made his way well into the executive mansion will never happen again.

Pierson told the House Oversight and Government Operations Committee on Tuesday that the breach was unacceptable.

Omar J. Gonzalez, an Army veteran who was armed with a knife, jumped the fence and made it much further into the White House than officials previously disclosed, according to lawmakers.

Pierson said she will make sure such a thing “never happens again.”