Trump called U.S. Secret Service Director Kimberly Cheatle's resignation “inevitable" on Newsmax Tuesday evening.

He also slammed the Secret Service for not getting to the bottom of what had happened yet.

"I have to feel safe. Otherwise, I guess, I wouldn't be able to do this stuff," Trump said.

"Now, they have really beefed it up. They should have beefed it up before," he said. "I know that we've been asking for them to beef it up here."

-ABC News' Soorin Kim, Kelsey Walsh and Lalee Ibssa

Sen. Chuck Grassley, R-IA, has released body-camera footage his office obtained from the Beaver County Emergency Services Unit taken soon after the assassination attempt on Donald Trump.

The graphic video, posted to X, shows a number of law enforcement officers standing on the roof where the shooter took his perch. The body of the deceased shooter is still there as the officers discuss the incident.

Grassley said the video was obtained in compliance with congressional requests.

"Bodycam footage provides more info than Secret Service will share w America," he said in the post. "We NEED detailed answers ASAP on security failures TRANSPARENCY BRINGS ACCOUNTABILITY."

The Secret Service has recommended that Trump's campaign stop holding rallies outdoors following the assassination attempt, sources familiar with the matter told ABC News.

The Washington Post first reported the news.

None of the rallies planned in the coming days are scheduled to be held outdoors. Conversations about upcoming rally sites have not included any outdoor venues, the sources said.

A campaign spokesperson did not immediately comment.

-ABC News' John Santucci, Katherine Faulders and Luke Barr

The new acting director of the Secret Service, Ron Rowe, pledged to "restore the faith and confidence of the American public and the people we are entrusted to protect" in a message to the agency workforce.

Rowe also mentioned Secret Service Director Kim Cheatle's resignation, saying, "This agency owes her a debt of gratitude that can never be repaid. Our organization is a better place because of her nearly three decades of service."