BUTLER, Pennsylvania  -  Donald Trump survived a weekend assassination attempt days before he is due to accept the formal Republican presidential nomination, in an attack that will further inflame the US political divide and has raised questions about the security lapses.

Trump, 78, had just begun a campaign speech in Butler, Pennsylvania, about 30 miles north of Pittsburgh, on Saturday when shots rang out, hitting the former president’s right ear and streaking his face with blood. “Fight! Fight! Fight!” Trump mouthed to supporters, pumping his fist, as Secret Service agents rushed him away. His campaign said he was doing well and appeared to have suffered no major injury besides a wound on his upper right ear.

The FBI identified 20-year-old Thomas Matthew Crooks of Bethel Park, Pennsylvania, as the suspect in what it called an attempted assassination. He was a registered Republican, according to state voter records and had made a $15 donation to a Democratic political action committee at the age of 17.

Law enforcement officials told reporters they had not yet identified a motive for the attack.

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 show the two locked in a close contest.

The shooting whipsawed the discussion around the presidential campaign, which had been focused for much of the past two weeks on Democrats’ questions as to whether Biden, 81, should drop out following a disastrous June debate performance.

The Biden campaign had been seeking to reset its message, depicting Trump as a danger to democracy for his continued false claims about election fraud but said on Saturday it was suspending its political advertising for now.

Secret Service agents fatally shot the suspect, the agency said, after he opened fire from the roof of a building about 150 yards (140 m) from the stage where Trump was speaking. An AR-15-style semiautomatic rifle used in the shooting was recovered near his body, according to sources.

One person who attended the rally was killed and two other spectators were critically wounded, the Secret Service said.

“In this moment, it is more important than ever that we stand United, and show our True Character as Americans, remaining Strong and Determined, and not allowing Evil to Win,” Trump said on his Truth Social service on Sunday.

Trump left the Butler area under Secret Service protection and later arrived at his golf club in Bedminster, New Jersey.

The Secret Service in a statement denied accusations by some Trump supporters that it had rejected campaign requests for additional security.

“The assertion that a member of the former President’s security team requested additional security resources that the US Secret Service or the Department of Homeland Security rebuffed is absolutely false,” said Secret Service spokesperson Anthony Guglielmi in a statement. “In fact, recently the US Secret Service added protective resources and capabilities to the former President’s security detail.”

While mass shootings at schools, nightclubs and other public places are a regular feature of American life, the attack was the first shooting of a US president or major party candidate since the 1981 attempted assassination of Republican President Ronald Reagan.

In 2011, Democratic then-Congresswoman Gabby Giffords was seriously wounded in an attack on a gathering of constituents in Arizona. Republican US Representative Steve Scalise was also badly wounded in a politically motivated 2017 attack on a group of Republican representatives practicing for a charity baseball game.

Giffords later founded a leading gun control organization, Scalise has remained a stalwart defender of gun rights.

The attack heightened longstanding worries that political violence could erupt during the presidential campaign and after the election. The concerns in part reflect the electorate’s polarization, with the country appearing bitterly divided into two camps with divergent political and social visions.

Americans fear rising political violence with two out of three respondents to a May survey saying they worried violence could follow the election.

Trump supporters stormed the US Capitol on Jan. 6, 2021, in an attempt to overturn his election defeat, fueled by his false claims that his loss was the result of widespread fraud. About 140 police officers were injured in the violence, four riot participants died that day, one police officer who responded died the following day and four responding officers later died by suicide.

Trump is due to receive his party’s formal nomination at the Republican National Convention, which kicks off in Milwaukee on Monday.

The shots appeared to come from outside the area secured by the Secret Service, the agency said.

Hours after the attack, the Oversight Committee in the Republican-led US House of Representatives summoned Secret Service Director Kimberly Cheatle to testify at a hearing scheduled for July 22.

Leading Republicans and Democrats quickly condemned the violence, as did foreign leaders.

“There’s no place for this kind of violence in America. We must unite as one nation to condemn it,” Biden said in a statement.

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 Scalise, the No. 2 House Republican.

“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. He unified his party around him after its support wavered briefly when his supporters attacked the US 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.