Former President Donald Trump says he was shot in the ear after a gunman perched on the roof of a nearby building opened fire at a rally in Butler, Pennsylvania, on Saturday — a harrowing incident that the FBI called an assassination attempt.

The shooting, which sent the country on edge on the even of the Republican National Convention, left one spectator dead, two others critically injured and sparked chaos at the event. As the former president spoke, shots crackled and Trump, hand to his ear, dropped to the ground where he was surrounded by agents before behind hustled off the stage into a waiting car amid the screams and confusion of the crowd.

The shooting being investigated by the FBI overseen by the Justice Department’s National Security Division as well as the U.S. attorney’s office in Pittsburgh and comes amid a heightened threat environment.

The Secret Service, in a statement, said that a shooter “fired multiple shots toward the stage from an elevated position outside of the rally venue” after which agents “neutralized the shooter, who is now deceased.”

The shooter fired as many as eight rounds from an AR-style rifle while perched on a rooftop adjacent to the venue and was 200-300 yards away at the time of the shooting, law enforcement sources told ABC News.

One spectator was killed and two others critically injured, the Secret Service said in a statement. The FBI believes they have identified the shooter although they are not releasing his name due to the sensitive point in the investigation, according to a law enforcement source. The early indication is that the shooter was a lone wolf, but the situation is fluid, the source said.

FBI Pittsburgh Special Agent in Charge Kevin Rojek said the agency was trying to assess the motive for the shooting and confirm the gunman’s identity. “It’s a matter of doing biometric confirmations, so there was no identification on the individual for example so we’re looking at photographs right now and we’re trying to run his DNA and get biometric confirmation.”

There appeared to be blood on Trump’s right ear as he was being taken off stage, and he could be seen mouthing “fight” and pumping his fist.

Pennsylvania State Police Lt. Col. George Bivens described a “chaotic scene” where law enforcement acted “heroically.” Bivens said officials were following up on reports about suspicious occurrences that they received prior to the shooting.