Attendees at a rally outside Pittsburgh for former President Trump described a chaotic scene as gunshots rang out and Trump was rushed offstage, blood trickling down his cheek.

“It is chaos. I have been told it is chaos,” Butler County Dist. Atty. Richard A. Goldinger told CNN. “It’s really crazy right now.”

In an interview with CBS News, an emergency room physician said he heard gunshots but initially thought they were firecrackers.

Then, someone cried out: “He’s been shot! He’s been shot!”

The doctor, who didn’t identify himself in the interview, said he went over to the man who had been injured and announced himself as an emergency department physician.

Supporters stand for the Pledge of Allegiance before former President Trump’s speech Saturday in Butler, Pa.

(Evan Vucci / Associated Press)

“The guy had spun around and was jammed between the benches. He had a headshot … there was lots of blood, and he had brain matter there,” said the man, who had blood spattered on his white T-shirt. “I did CPR, did chest compressions as well and breathed for him.”

As he was speaking, an emergency helicopter whirred in the distance.

Pennsylvania Senate candidate Dave McCormick was sitting in the front row at the rally when he heard gunfire. The Republican told Politico that someone behind him appeared to have been shot but was unsure the extent of the injury.

The alleged shooter is dead, as is another person who was attending the rally, Goldinger told CNN.

A witness on BBC said he noticed a man with a rifle “bear-crawling” on the roof of a building about 50 feet from where he was watching Trump at the rally. The suspect was on the roof for at least three or four minutes before shots erupted, the witness said.

The witness said he was not inside the rally but could hear Trump speak from a field adjacent to the rally at Brenckle’s Farms and Greenhouses in Butler, Pa.

Police snipers return fire during Saturday’s campaign rally for former President Trump in Butler, Pa.

(Gene J. Puskar / Associated Press)

“We could clearly see him with a rifle, absolutely. We’re pointing at him,” he said on BBC. “The police are down there running around on the ground … they didn’t know what was going on.”

After the suspect opened fire, the witness said he saw Secret Service shoot the suspect, crawl up the roof and make sure he was dead.

The witness, who was wearing a red Trump 2020 visor, questioned why Secret Service did not pull Trump off the stage in those several minutes.

“I’m thinking to myself: Why is Trump still speaking? Why have they not pulled him off the stage?” he said. “I’m standing there pointing at him [the suspected shooter] for two, three minutes.

“Why is there not Secret Service on all of these roofs here?” he said. “I mean, this is not a big place.”