BUTLER, Pennsylvania -- Donald Trump was shot in the ear during a Saturday campaign rally, in an attack that left the Republican presidential candidate's face streaked with blood and prompting his security agents to swarm him, before he emerged and pumped his fist in the air, mouthing the words "Fight! Fight! Fight!" 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.

Law enforcement officials told reporters they had tentatively identified a suspected shooter but were not ready to do so publicly. They also said they not yet identified a motive.

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 the fist bump, then agents rushed him to a black SUV.

"I was shot with a bullet that pierced the upper part of my right ear," Trump said later on his Truth Social platform following the shooting in Butler, Pennsylvania, about 30 miles (50 km) north of Pittsburgh. "Much bleeding took place."

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.

Leading Republicans and Democrats quickly condemned the violence.

The Trump campaign said he was "doing well."

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."

Republican US 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.

It was the first shooting of a US president or major party candidate since the 1981 attempted assassination of Republican President Ronald Reagan.

Pennsylvania Governor Josh Shapiro said Trump has left the Butler area under the protection of the US Secret Service with the assistance of the Pennsylvania state police. Republican US Representative Daniel Meuser told CNN Trump was headed to Bedminster, New Jersey, where he has a golf club.

Ron Moose, a Trump supporter at the rally, said 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."

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.

CNN, citing sources, said the FBI had identified the suspected shooter, a 20-year-old Pennsylvania man.

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.

Americans fear rising political violence, recent Reuters/Ipsos polling shows, with two out of three respondents to a May survey saying they worried 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 US 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."

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 US Capitol on Jan. 6, 2021, attempting to overturn his 2020 election defeat. (Reuters)