Suddenly there was a volley of "pops" - what sounded like gunshots. Trump immediately clutched his right ear, looked at the blood on his hand and then quickly dropped to the ground behind the podium.

The crowd screamed and those in the bleachers behind him crouched.

A half dozen Secret Service agents ran onto the stage and piled on and around Trump, who was kneeling behind the podium. Other law enforcement officers armed with rifles also took to the stage.

There was a second volley of apparent gunshots.

The Secret Service agents kept Trump on the ground for 25 seconds. Someone could be heard shouting: "Shooter is down!"

Someone else yelled: "Move!" as many in the crowd continued to scream.

The agents raised Trump to his feet, his red "Make America Great Again" baseball cap no longer on his head, his hair disheveled, his ear bloodied and streaks of blood smeared on his face.

"Let me get my shoes. Let me get my shoes," Trump said, as the agents lifted him from the ground. He then said: "Wait, wait, wait", before he started pumping his fist.

One agent raised his arm above Trump's head, to shield it from more potential shots.

Trump continued to pump his fist towards the crowd, mouthing "fight." Many in the crowd began chanting "USA, USA".

As the Secret Service agents surrounded Trump and moved him to a nearby black SUV, Trump continuously raised his fist as they pushed him into the vehicle, to more chants of "USA!"

Shane Chesher, 37, who had been sitting directly behind Trump, said, "It sounded like pop, pop, pop. I thought it was a prank, like fireworks. Then I watched it get real very quickly when President Trump went down and Secret Service came in and more shots went off."

He said children close to him were screaming. "Everyone started panicking. It was chaos."

Chesher, who came from his hometown of Pittsburgh for the rally and handles maintenance at a church, said the sight of terrified children around him prompted him to say the Lord's Prayer. Once he started, others joined in.

"It was such a powerful moment. I think it gave people a lot of peace."

An eyewitness told the BBC he saw the shooter climb on the roof of a low-rise building just outside the security perimeter with a rifle and shouted to nearby police officers to alert them to the potential threat. Police initially seemed confused and did not immediately respond to the warning, he said.

"Next thing you know, five shots rung out," he said.

"Secret Service blew his head off. They crawled up on the roof, they had their guns pointed at him, made sure he was dead, he was dead, and that was it, it was over."

Ben Maser was outside the rally perimeter, listening to Trump, when he noticed two officers seemingly looking for someone. Maser, a 41-year old welder, started scanning the area too.

"I saw the guy on the roof. I told the officer that he was up there. He went about looking for him," said Maser.

Maser said he could not describe the man on the roof but saw he was wearing a grey T-shirt.

Jim Moore, 57, was in the grandstand behind the stage when the shots were fired. He said a man about five rows up from him was shot and went down. He said agents came and escorted him behind the grandstand, where they tended his wounds.

"The guy right behind us got shot. After they got Trump out of the way, they took him and walked him down - he was walking - they took him behind the bleachers and laid him down," said Moore, who is from Beaver County, Pennsylvania.

Two women in their seventies sitting near the stage told Reuters they saw two people go down in the bleachers after the shooting and police tending to them.