Secret Service Director Julia Pierson offered her resignation Wednesday after several security breaches affecting the White House and President Obama became public, Department of Homeland Security Secretary Jeh Johnson announced Wednesday.

"Today Julia Pierson, the Director of the United States Secret Service, offered her resignation, and I accepted it. I salute her 30 years of distinguished service to the Secret Service and the Nation," Johnson said in a statement.

"As an interim Acting Director of the Secret Service, I am appointing Joseph Clancy, formerly Special Agent in Charge of the Presidential Protective Division of the Secret Service. Mr. Clancy retired from the Secret Service in 2011. I appreciate his willingness to leave his position in the private sector on very short notice and return to public service for a period."

"I think it's in the best interest of the Secret Service and the American public if I step down," Pierson said in an interview with Bloomberg News after the announcement. "Congress has lost confidence in my ability to run the agency. The media has made it clear that this is what they expected."

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"I can be pretty stoic about it, but not really," she said. "It's painful to leave as the agency is reeling from a signifcant security breach."

Johnson said he has asked Deputy Secretary of Homeland Security Alejandro Mayorkas and the agency's general counsel to take charge of the ongoing Secret Service inquiry into the Sept. 19 fence-jumping incident in which a man entered the White House. The review should be completed by Nov. 1.

Additionally, Johnson plans to appoint a panel of independent experts to to review the incident. The panelists will be named shortly and will deliver an assessment and recommendations for the security of the White House compound by Dec. 15, as well as recommendations for a new director.

"I will also request that the panel advise me about whether it believes, given the series of recent events, there should be a review of broader issues concerning the Secret Service. The security of the White House compound should be the panel's primary and immediate priority," Johnson said.

Pierson's resignation comes after she faced blistering criticism Tuesday at a congressional hearing called after a 42-year-old Texas man, Omar J. Gonzalez, was able to scale the White House fence, enter the unlocked front doors of the building, and run all the way into the East Room before he was apprehended by an off-duty Secret Service agent.

White House Press Secretary Joshua Earnest said that President Obama called Pierson Wednesday afternoon to "express his appreciation for her service to the agency and to the country."

Asked why the president accepted her resignation after showing support for the past several days, Earnest said Pierson "believed that it was in the best interests of the agency to which she had dedicated her career. [Secretary Johnson] agreed with that assessment. The president did as well."

When she testified before the House Oversight and Government Reform Committee Tuesday, Pierson said, "It is clear that our security plan was not executed properly. I take full responsibility; what happened is unacceptable and it will never happen again,"

But the apology was not enough for lawmakers, who expressed concern over both the basic competence of the agency charged with protecting the president and the fact that the Secret Service seemed to offer misleading information, or simply withhold it from the public entirely.

The day before Pierson's appearance, CBS News learned that Gonzalez made it much farther inside the White House than just inside the front doors, as the agency previously said - a "false report," as House Oversight and Government Reform Committee Chairman Darrell Issa, R-California, called it. On Sunday, a Washington Post report revealed that it took the Secret Service took four days to realize a gunman had fired at and hit the White House in 2011, despite the fact that some agents on duty believed the building had sustained fire.

Just after the hearing, there were more revelations: during Mr. Obama's visit to the Centers for Disease Control, a security contractor for the CDC, who had been previously arrested, rode in an elevator with the president while carrying a gun.

Pierson took over as the agency's chief in March 2013 after the retirement of former director Mark Sullivan, who struggled with a prostitution scandal among agents traveling with the president and a pair of gate-crashers at a state dinner. Prior to taking over, Pierson had served as the Secret Service Chief of Staff since 2008.

"I'm disappointed that I didn't have an opportunity to implement structural and operational changes in the agency," she told Bloomberg. "I had a vision for the future. It's 31 years of service and a firm understanding of the organization."

Members of Congress at first indicated they wanted to hear Pierson out before demanding further action. But her testimony Tuesday ultimately failed to restore their confidence in her ability to lead the agency.

"I want her to go if she cannot restore trust in the agency, and if she cannot get the culture back in order," the House Oversight Committee's top Democrat, Rep. Elijah Cummings, told CNN Wednesday. "I told her that she's got a tall order there."

Rep. Jason Chaffetz, R-Utah, who has been deeply involved in investigating the Secret Service, told Bloomberg News earlier Wednesday, "The president should fire her or at least she should resign."

Pierson's resignation will not be the end of the scrutiny for the Secret Service, however. House Homeland Security Committee Chairman Michael McCaul, R-Texas, announced Tuesday he was creating a blue ribbon commission of outside experts to conduct an independent and comprehensive review of the Secret Service.

And House Minority Leader Nancy Pelosi, D-Calif., told reporters Wednesday that Congress needed answers regardless of whether Pierson remained at the helm of the agency.

"Whether she does [resign] or not I think we need an independent investigation. Her leaving doesn't end the need for us to know a lot more about what is happening," Pelosi said.