U.S. Secret Service Director Kimberly Cheatle, who came under scrutiny for the agency's failure to prevent the assassination attempt on former President Donald Trump, has resigned.

Cheatle had faced calls to step down since the shooting at a Trump rally on July 13, which left one attendee dead and two others critically injured.

She announced her resignation Tuesday morning in an email to Secret Service employees, which was obtained by ABC News.

"The Secret Service's solemn mission is to protect our nation's leaders and financial infrastructure. On July 13th, we fell short on that mission," she wrote. "The scrutiny over the last week has been intense and will continue to remain as our operational tempo increases. As your Director, I take full responsibility for the security lapse."

Ron Rowe, the Secret Service deputy director, has been appointed as acting director of the agency.

"We will restore the faith and confidence of the American public and the people we are entrusted to protect," he wrote in a message to employees, obtained by ABC News.

Rowe is a 24-year veteran of the U.S. Secret Service.

In a statement following Cheatle's resignation, President Joe Biden said he was "grateful" to Cheatle for her service and that the independent review into the shooting would continue.

"As a leader, it takes honor, courage, and incredible integrity to take full responsibility for an organization tasked with one of the most challenging jobs in public service," Biden said.

Homeland Security Secretary Alejandro Mayorkas thanked Cheatle for her "lifelong devotion to our country" and for leading "the Secret Service with skill, honor, integrity, and tireless dedication."

"She is deeply respected by the men and women of the agency and by her fellow leaders in the Department of Homeland Security," Mayorkas said in a statement. "I am proud to have worked with Director Cheatle and we are all grateful for her service."

In an interview with ABC News after the attack, Cheatle called the incident "unacceptable" and said it was her responsibility to ensure nothing like it would happen again.

"The buck stops with me," she said. "I am the director of the Secret Service, and I need to make sure that we are performing a review and that we are giving resources to our personnel as necessary."

Cheatle said during the interview she would not resign from her role -- a claim she repeated during House testimony on Monday.

During the contentious hearing, Cheatle called the assassination attempt on Trump the "most significant operational failure at the Secret Service in decades."

"The Secret Service's solemn mission is to protect our nation's leaders. On July 13, we failed," Cheatle said in her testimony before the House committee. "As the director of the United States Secret Service, I take full responsibility for any security lapse. We are fully cooperating with ongoing investigations. We must learn what happened."

Cheatle told the committee that she would move "heaven and earth" to ensure that what occurred will never happen again.

"Our mission is not political. It is literally a matter of life and death, as the tragic events on July 13 remind us of that," she said. "I have full confidence in the men and women of the Secret Service. They are worthy of our support in executing our protective mission."

Cheatle had faced calls to resign from both Republicans and Democrats after the shooting. John Comer, R-Ky., chairman of the House Oversight Committee, told Cheatle in his opening statement at the hearing that he was among those who believe she should resign.

By the end of the hearing, Rep. Jamie Raskin, D-Md., the ranking member of the committee, joined in the calls for Cheatle to resign, saying that the director "has lost the confidence of Congress at a very urgent and tender moment in the history of the country and we need to quickly move beyond this." Following the hearing, Raskin joined Comer in sending Cheatle a letter requesting her resignation.

Critics questioned how the Secret Service could have failed to safeguard the rally area from such an attack, particularly following reports the shooter had been spotted before he opened fire and identified as potentially suspicious.

Cheatle previously told ABC News "a very short period of time" passed between then and the shooting.

"I don't have all the details yet, but it was a very short period of time," she said. "Seeking that person out, finding them, identifying them, and eventually neutralizing them took place in a very short period of time, and it makes it very difficult."

Cheatle also said that local authorities were tasked with securing the building where the alleged shooter fired the shots before being taken out by a Secret Service sniper, and confirmed that local police were present inside the building while the shooter was on the roof.

"In this particular instance, we did share support for that particular site and that the Secret Service was responsible for the inner perimeter," Cheatle said. "And then we sought assistance from our local counterparts for the outer perimeter. There was local police in that building -- there was local police in the area that were responsible for the outer perimeter of the building."

Some of the criticism of Cheatle has focused on her being a woman, with prominent conservatives, like Rep. Tim Burchett, R-Tenn., calling her a "DEI hire" and female Secret Service agents in general as having "physical limitations" that should prevent them from serving.

Cheatle testified before the GOP-led House Oversight Committee on Monday. In a statement announcing the hearing, chairman Comer said, "Americans demand answers" from Cheatle.

"The United States Secret Service has a no-fail mission, yet it failed on Saturday when a madman attempted to assassinate President Trump, killed an innocent victim, and harmed others," Comer said. "We are grateful to the brave Secret Service agents who acted quickly to protect President Trump after shots were fired and the American patriots who sought to help victims, but questions remain about how a rooftop within proximity to President Trump was left unsecure."

Cheatle, who was appointed by Biden in 2022, was one of only two women to ever serve as director of the Secret Service. Previously, she had been the first woman to serve as the agency's assistant director of protective operations.

Before her appointment, she was the senior director in global security at PepsiCo. Before that, she had served with the Secret Service for more than 25 years, including on Biden's security detail while he was vice president.