Secret Service Director Kimberly Cheatle steps down amid ...

WASHINGTON — U.S. Secret Service Director Kimberly Cheatle has stepped down after widespread calls from lawmakers for her to resign following the assassination attempt on former President Donald Trump, three sources told NBC News.

In her resignation letter, obtained from a senior official who received it, Cheatle wrote that the "scrutiny over the last week has been intense and will continue to remain as our operational tempo increases." She added she takes "full responsibility for the security lapse."

"In light of recent events, it is with a heavy heart that I have made the difficult decision to step down as your Director," wrote Cheatle, who had led the agency since September 2022.

It's unclear when her last day will be.

In a statement, President Joe Biden thanked Cheatle for her service, saying he will appoint her successor to lead the Secret Service "soon." After the assassination attempt on Trump, Biden ordered an independent review to assess what happened and said Tuesday that he looks forward to reading its conclusions.

"We all know what happened that day can never happen again," Biden said.

In response to the news of her resignation, Trump wrote on Truth Social: "The Biden/Harris Administration did not properly protect me, and I was forced to take a bullet for Democracy. IT WAS MY GREAT HONOR TO DO SO!"

House Oversight Committee Chairman James Comer, R-Ky., said in a statement Tuesday that Cheatle "instilled no confidence" when she faced questions Monday from angry lawmakers from both parties who were exasperated over the Secret Service’s failure to protect Trump.

“I’m not going to get into specifics of the day,” Cheatle testified, citing an ongoing investigation. “There was a plan in place to provide overwatch, and we are still looking into responsibilities.”

Both Democratic and Republican committee members said she should resign over her "incompetence" and her "lame excuses."

“You’re full of s--- today!” Rep. Nancy Mace, R-S.C., said, slamming Cheatle for dodging questions and being “completely dishonest” about her cooperation with the committee.

Her responses didn’t satisfy the leaders of the House Oversight Committee, which held the hearing Monday and had subpoenaed her.

“Today, you failed to provide answers to basic questions regarding that stunning operational failure and to reassure the American people that the Secret Service has learned its lessons and begun to correct its systemic blunders and failures,” Comer and Ranking Member Jamie Raskin, D-Md., wrote in a joint letter to Cheatle hours after the hearing. 

The two members said that the committee and the American people “demand serious institutional accountability and transparency that you are not providing,” especially during a presidential election year.  

“We call on you to resign as Director as a first step to allowing new leadership to swiftly address this crisis and rebuild the trust of a truly concerned Congress and the American people,” they wrote.

Speaker Mike Johnson, R-La., and several other top Republicans, including House Majority Leader Steve Scalise, R-La., and Senate Republican Conference Chairman John Barrasso, R-Wyo., also called on Cheatle to resign. 

Before her resignation Tuesday, several Republican lawmakers said that they planned to file impeachment articles against Cheatle.

“She needs to go,” Barrasso, told NBC News’ Hallie Jackson after a Senate briefing on the shooting last week.

In an interview with ABC News last week, Cheatle said the “buck” stopped with her.

The agency was conducting a review of the incident, she said, and she did not have all the details about what happened. But Cheatle said there had been a “very short” period between when the shooter, Thomas Matthew Crooks, 20, was reported as potentially suspicious and when he began shooting from a rooftop at the July 13 rally.

After a Senate briefing Wednesday on the assassination attempt, two sources familiar with the proceedings said that window of time was 62 minutes.

The sources also said Secret Service agents spotted Crooks on a rooftop 10 minutes before Trump took the stage, and 20 minutes elapsed before he opened fire.  

Trump has said he was shot in the upper part of his right ear. A former fire official, Corey Comperatore, died in the shooting. Two others were injured and hospitalized, and their conditions have improved.

This is a developing story. Please check back for updates.