[Source: Reuters]

Donald Trump said he was headed for Milwaukee on Sunday, where Republicans will formally make him their presidential nominee later this week after he survived an assassination attempt that further inflames an already bitter U.S. political divide.

President Joe Biden, a Democrat, said he had ordered a review of how a 20-year-old man carrying an AR-15-style rifle managed on Saturday to get close enough to shoot from a rooftop at Trump, who as a former president has lifetime protection by the U.S. Secret Service.

Trump, 78, was holding a campaign rally in Butler, Pennsylvania – one of the states expected to be most competitive in the Nov. 5 election – when shots rang out, hitting his right ear and streaking his face with blood. His campaign said he was doing well and appeared to have suffered no major injury besides a wound on his upper right ear.

Trump is due to receive his party’s formal nomination at the Republican National Convention, which kicks off in Milwaukee, Wisconsin, on Monday. RNC Chairman Michael Whatley said on Fox News on Sunday that authorities are working together to safeguard the venue, where officials have spent months making security preparations.

He said he would be leaving in the afternoon.

The FBI identified 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 yet to identify a motive for the attack. Both Republicans and Democrats will be looking for evidence of Crooks’ political affiliation as they seek to cast the rival party as representing extremism.

Trump and Biden are locked in a close election rematch, according to most opinion polls including those by Reuters/Ipsos.

The shooting whipsawed the discussion around the presidential campaign, which had recently focused on 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.

The firearm was legally purchased by the suspect’s father, ABC and the Wall Street Journal reported, citing sources. Bomb-making materials were found in the suspect’s car, the Associated Press reported, citing sources.