WASHINGTON: The head of the United States Secret Service is stepping down overthe assassination attemptagainst former President Donald Trump, after days of mounting pressure and criticism for failing to prevent the shooting.

The Associated Pressnews agency said Kimberly Cheatle sent an email to staff on Tuesday announcing her plans to step down.

Cheatle hasbeen under pressurefrom US lawmakers to resign as questions continue to swirl around security protocols at Trump’s July 13 rally in Pennsylvania, where the former president and Republican presidential nominee was shot in the ear.

"I take full responsibility for the security lapse,” Cheatle said in the email to staff. "In light of recent events, it is with a heavy heart that I have made the difficult decision to step down as your director.”

The Secret Service chiefhad faced angry questionsduring a US congressional committee hearing on Monday over the agency’s security plan at the Trump rally.

"The assassination attempt on former President Donald Trump on July 13 is the most significant operational failure at the Secret Service in decades,” Cheatle told lawmakers.

"There clearly was a mistake and we will make every effort to make sure that this never happens again,” she said.

Trump was shot in the ear by a gunman that witnesses say had taken up a position on a rooftop with a direct line of sight of the rally stage, raising questions about what security measures were put in place before the event.

USPresident Joe Bidenhas ordered an independent review of security protocols at the rally, where one attendee was killed and two others were seriously injured.

But lawmakers had been pushing for more immediate answers from Cheatle and other US law enforcement agency chiefs, including Homeland Security Secretary Alejandro Mayorkas and FBI Director Christopher Wray.

In a statement on Tuesday, Biden thanked Cheatle for her decades of public service and said he planned to appoint a new Secret Service director soon.

"The independent review to get to the bottom of what happened on July 13 continues, and I look forward to assessing its conclusions. We all know what happened that day can never happen again,” Biden said.