Shafaq News/ Former President Donald Trump was rushed off stage after gunshots erupted at a rally in Pennsylvania in what the FBI described as an assassination attempt.

Law enforcement sources told CNN that a shooter was positioned on a building rooftop just outside the venue where Trump was holding his rally in Butler, Pennsylvania. Footage showed Trump grimace and raise a hand to his right ear before ducking as several sharp cracks and a series of shots rang out.

Trump was quickly swarmed by US Secret Service agents and dragged off stage to a waiting vehicle. He raised a fist as he was bundled into the car.

In a post to his social network, Trump said a bullet pierced the "upper part" of his right ear. Earlier, his spokesperson said he was receiving treatment at a local medical center.

"I knew immediately that something was wrong when I heard a whizzing sound, shots, and immediately felt the bullet ripping through the skin," Trump wrote. "Much bleeding took place, so I realized then what was happening."

Blood was clearly visible on Trump's ear and face as protection officers rushed him away.

The suspect was shot dead at the scene by US Secret Service officers, according to the agency's spokesperson, Anthony Guglielmi. He added that one bystander was killed in the shooting and two others were critically injured.

At a news conference Saturday night, the FBI said the agency is working to identify the gunman through "biometric confirmations" as he did not carry identification. Officials later revealed that all three victims were male.

Speaking from his home state of Delaware, President Joe Biden condemned the attack, calling it "sick."

"There's no place in America for this kind of violence," he said. "Everybody must condemn it."

The White House later said President Biden, who was planning to stay in Delaware for the weekend, had spoken with Trump before returning to Washington, DC, so he could continue receiving briefings from law enforcement.

Trump remains locked in a tight contest with President Biden, the presumptive Democratic nominee, in a re-match of the 2020 election.

Politicians of both parties joined Biden in condemning the apparent attack. Former President Barack Obama said there "is absolutely no place for political violence in our democracy" and that he was "relieved that former President Trump wasn't seriously hurt."

In a message shared on social media, Ivanka, Trump's daughter, who previously served as a top adviser in the White House, thanked supporters for their prayers and highlighted the bravery of law enforcement officers.

"Thank you for your love and prayers for my father and for the other victims of today's senseless violence in Butler, Pennsylvania. I am grateful to the Secret Service and all the other law enforcement officers for their quick and decisive actions today. I continue to pray for our country," Ivanka said.