Pop, pop, pop, then a bloodied Trump rushed from election rally

Donald Trump was standing on a stage behind a podium, six minutes into his speech at an outdoor rally in Butler, Pennsylvania, his head turned to the right, under a clear sky and in broiling heat.

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 dishevelled, 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!"

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."

Ron Moose, a Trump supporter who was in the crowd, told Reuters he heard about four shots. "I saw the crowd go down and then Trump ducked also real quick," he said. "Then the Secret Service all jumped and protected him as soon as they could. We are talking within a second they were all protecting him."

Jim Moore, 57, was in the grandstand behind the stage. 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.