The shooter was dead, one rally attendee was killed and two other spectators were injured, the Secret Service said in a statement. The incident was being investigated as an assassination attempt, a source told Reuters.
Trump, 78, had just started his speech when the shots rang out. He grabbed his right ear with his right hand, then brought his hand down to look at it before dropping to his knees behind the podium before Secret Service agents swarmed and covered him. He emerged about a minute later, his red "Make America Great Again" hat knocked off, and could be heard saying "wait, wait," before agents ushered him into a vehicle.
"I was shot with a bullet that pierced the upper part of my right ear," Trump said on his Truth Social platform following the shooting in Butler, Pennsylvania, about 30 miles (50 km) north of Pittsburgh. "Much bleeding took place."
The shooter's identity and motive were not immediately clear. Leading Republicans and Democrats quickly condemned the violence.
The Trump campaign said he was "doing well." Bloomberg reported he had been released from the hospital.
The shooting occurred less than four months before the Nov. 5 election, when Trump faces an election rematch with Democratic President Joe Biden. Most opinion polls including those by Reuters/Ipsos show the two locked in a close contest.
Biden said in a statement: "There’s no place for this kind of violence in America. We must unite as one nation to condemn it."
Biden spoke with Trump following the shooting, a White House official said.
Republican U.S. Representative Ronny Jackson of Texas told Fox News his nephew had been wounded at the rally.
The shooting raised immediate questions about security failures by the Secret Service, which provides former presidents including Trump with lifetime protection.
WITNESS ACCOUNT
Ron Moose, a Trump supporter who was at the rally, described the chaos: "I heard about four shots and I saw the crowd go down and then Trump ducked also real quick. 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."
Moose said he then saw a man running and being chased by officers in military uniforms. He said he heard additional shots, but was unsure who fired them. He noted that by then snipers had set up on the roof of a warehouse behind the stage.
The BBC interviewed a man who described himself as an eyewitness, saying he saw a man armed with a rifle crawling up a roof near the event. The person, who the BBC did not identify, said he and the people he was with started pointing at the man, trying to alert security.
The shots appeared to come from outside the area secured by the Secret Service, the agency said. The FBI said it had taken the lead in investigating the attack.
REPUBLICANS, DEMOCRATS DECRY VIOLENCE
Trump is due to receive his party's formal nomination at the Republican National Convention, which kicks off in Milwaukee on Monday.
"This horrific act of political violence at a peaceful campaign rally has no place in this country and should be unanimously and forcefully condemned," Republican House Speaker Mike Johnson said on social media.
Democratic Senate Majority Leader Chuck Schumer said he was horrified by what happened and was relieved Trump was safe. "Political violence has no place in our country," he said.
Biden's campaign was pausing its television ads and halting all other outbound communication, a campaign official said on Saturday.
Americans fear rising political violence, recent Reuters/Ipsos polling shows, with two out of three respondents to a May survey saying they feared violence could follow the election.
Some of Trump's Republican allies said they believed the attack was politically motivated.
"For weeks Democrat leaders have been fueling ludicrous hysteria that Donald Trump winning re-election would be the end of democracy in America," said U.S. Representative Steve Scalise, the No. 2 House Republican, who survived a politically motivated shooting in 2017. "Clearly we’ve seen far left lunatics act on violent rhetoric in the past. This incendiary rhetoric must stop."
Hardline Republican Representative Marjorie Taylor Greene said, "Democrats wanted this to happen. They’ve wanted Trump gone for years and they’re prepared to do anything to make that happen."
Trump, who served as president from 2017-2021, easily bested his rivals for the Republican nomination early in the campaign and has largely unified around him the party that had briefly wavered in support after his supporters attacked the U.S. Capitol on Jan. 6, 2021, attempting to overturn his 2020 election defeat.
The businessman and former reality television star entered the year facing a raft of legal worries, including four separate criminal prosecutions. He was found guilty in late May of trying to cover up hush money payments to a porn star, but the other three prosecutions he faces -- including two for his attempts to overturn his defeat -- have been ground to a halt by various factors including a Supreme Court decision early this month that found him to be partly immune to prosecution.
Trump contends without evidence that all four prosecutions have been orchestrated by Biden to try to prevent him from returning to power.
Republican U.S. Senate candidate David McCormick, who was seated in the front row at the rally, said he had started to go up on stage when Trump said he would have him come up later.
"Within a minute or two, I heard the shots ... It was clear it was gunfire," he told Reuters in an interview. "It felt like it was an assassination attempt ... It was terrifying."
