United States Secret Service director Julia Pierson has resigned after a series of security lapses came to light that showed gaping holes in the protective cocoon around President Barack Obama.
Ms Pierson, who had been in her position since March 2013, faced growing calls from lawmakers to step down in the fallout from a 19 September incident in which war veteran clambered over the White House fence, sprinted across the lawn and got deep inside the mansion before he was stopped.
Ms Pierson told a congressional committee on Tuesday she took "full responsibility" for security lapses. She tendered her resignation to Homeland Security Secretary Jeh Johnson, who accepted it.
Her resignation came the day after it was disclosed that in a violation of protocol, an armed private security contractor rode on an elevator with President Obama in Atlanta earlier this month and took pictures and video of the president on his phone.
White House spokesperson Josh Earnest said President Obama believed Ms Pierson's resignation was in the best interest of the agency, and that "recent and accumulating" reports of security lapses led the president to conclude new leadership was needed at the Secret Service.
Calls for Ms Pierson to step down had grown on Capitol Hill prior to her resignation. The 30-year Secret Service veteran had failed to inspire confidence among lawmakers from both parties during a three-and-a-half-hour grilling on Tuesday before the House Oversight and Government Reform Committee.
In response to calls from lawmakers for an independent probe into the 19 September fence-jumping incident, the Homeland Security Department will establish a panel of independent experts to investigate what happened.
Mr Earnest said the group will recommend changes to how the Secret Service operates and suggest who might become the next permanent Secret Service director. A veteran of the agency's presidential protection division, Joseph Clancy, was named acting director in the meantime.
Republican Representative Jason Chaffetz, who chairs a national security oversight subcommittee, questioned Ms Pierson during the hearing on the number of times she had briefed President Obama on incidents this year where his safety had been compromised.
She replied that there was only one such briefing - after the fence jumper incident. She made no mention of the Atlanta incident.
The omission prompted Chaffetz to call for her resignation and he was later followed by others.