Former President Donald Trump was rushed off the stage after he was shot on the side of his ear at a rally in Pennsylvania on Saturday.

The campaign said he was safe in a post on Truth Social saying that the bullet "pierced the upper part of my right ear."

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

One spectator from the rally is dead, and two were critically injured, according to Secret Service spokesperson Anthony Guglielmi. The shooter is dead, he said.

Trump thanked law enforcement in his online statement and extended condolences to the families of the people killed and injured.

"It is incredible that such an act can take place in our Country," he wrote.

The shots were fired from outside of the U.S. Secret Service security perimeter for the rally, according to three senior U.S. law enforcement officials.

The suspected shooter fired from an elevated position outside of the rally, Guglielmi said in the Secret Service statement. He added that Secret Service personnel "neutralized the shooter."

Trump was about six minutes into his speech when he reached for the side of his face as popping sounds rang out. He then crouched down as Secret Service agents rushed the stage and surrounded him. He was quickly escorted into a vehicle, walking off the stage with agents on all sides.

Trump pumped his fists in the air as he was escorted off of the stage. The crowd cheered as the former president raised his arms.

Reporters on the scene saw smoke and heard what they initially thought were fireworks before everyone ducked and law enforcement encircled Trump.

A doctor attending the event told NBC News that he saw a man suffer a gunshot wound to the head and helped carry him from the site of the rally. Speaking in a parking lot near the event, a mother and son who were attending the rally told NBC News that they saw people in the crowd who were injured and carried away.

People remained at the scene for 10 to 15 minutes after Trump was taken away, after which they were then told it was an active crime scene and all attendees were escorted out.

The Secret Service has requested that the FBI and the U.S. attorney’s office help with the investigation into the shots fired, according to two senior U.S. law enforcement officials.

The FBI said in a statement that personnel are on the scene, and they will work jointly with the Secret Service investigating the incident as an assassination attempt.

There is currently no sign that the attack has any link to a foreign actor, according to a U.S. official.

Trump's spokesperson Steven Cheung said that the former president "thanks law enforcement and first responders for their quick action during this heinous act."

"He is fine and is being checked out at a local medical facility," Cheung said. "More details will follow."