US Secret Service director Kimberly Cheatle has resigned after the agency came under harsh scrutiny for its failure to stop a would-be assassin from wounding former President Donald Trump during a campaign rally.

The agency did not immediately respond to a request for comment.

The Secret Service, which is responsible for the protection of current and former US presidents, faces a crisis after a gunman was able to fire on Trump from a roof overlooking the outdoor rally in Butler, Pennsylvania on July 13.

“I take full responsibility for the security lapse,” Cheatle said in an email to staff on Tuesday, the Associated Press reported.

A screengrab shows Republican presidential candidate former President Donald Trump being rushed offstage after the shooting. Photo / Getty Images 

“In light of recent events, it is with a heavy heart that I have made the difficult decision to step down as your director.”

Cheatle faced bipartisan condemnation when she appeared before the House of Representatives Oversight Committee on Monday, declining to answer questions from frustrated lawmakers about the security plan for the rally and how law enforcement responded to the suspicious behaviour of the gunman.

Several Republican and Democratic lawmakers called on her to resign.

Trump, the Republican presidential candidate, was grazed in the right ear and a rally attendee was killed in the gunfire.

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Law enforcement react after shots were fired at the rally of Republican presidential candidate Donald Trump. Photo / Getty

The gunman, identified as a 20-year-old Thomas Crooks, was shot and killed by a Secret Service sniper.

Cheatle, who has led the agency since 2022, told lawmakers she took responsibility for the shooting and called it the largest failure by the Secret Service since then-President Ronald Reagan was shot in 1981.

The Secret Service faces investigations from multiple congressional committees and the internal watchdog of the US Department of Homeland Security, its parent organisation, over its performance.

US President Joe Biden, who has ended his re-election campaign, has also called for an independent review.

Much of the criticism has focused on the failure to secure the roof of an industrial building where the gunman was perched about 140 metres from the stage where Trump was speaking.

The rooftop was declared outside the Secret Service security perimeter for the event, a decision criticised by former agents and politicians.

Cheatle held a top security role at PepsiCo when Biden named her Secret Service director in 2022.

She previously served 27 years in the agency.

Former US President Donald Trump was hit in his right ear in a shooting at his rally in the US state of Pennsylvania. Infographic / Getty Images

She took over following a series of scandals involving the Secret Service that scarred the reputation of an elite and insular agency.

Ten Secret Service agents lost their jobs after revelations they brought women, some of them prostitutes, back to their hotel rooms ahead of a trip to Colombia by then-President Barack Obama in 2012.

The agency also faced allegations that it erased text messages from about the time of the January 6, 2021 riots on the US Capitol.

Those messages were later sought by a congressional panel probing the riot.

The US House of Representatives said on Tuesday it was forming a bipartisan task force to investigate the shooting of Trump.

The panel, comprised of seven Republicans and six Democrats, will make recommendations for reforms to relevant government agencies and will have subpoena authority, according to a statement from Republican House Speaker Mike Johnson and Democratic leader Hakeem Jeffries.

At a hearing on Monday, the House Oversight Committee’s Republican chairman James Comer and top Democrat Jamie Raskin – normally bitterly divided on most issues – each called on Cheatle to resign.

“The security failures that allowed an assassination attempt on Donald Trump’s life are shocking,” Johnson said in a statement, adding the task force would move quickly to “make certain such failures never happen again”.

He said House lawmakers will vote on a resolution this week to establish the force and its members.