The shooter, along with one bystander who was there to attend the rally, died.

As gunshots were heard, Trump, who was just six minutes into his election speech, was seen clutching a hand to his right ear, where blood was visible across his cheek and mouth.

Two other spectators were injured, the Secret Service said in a statement. The incident was being investigated as an assassination attempt.

Secret Service agents were quick to respond and surrounded Trump while escorting him off the stage, as he raised a fist to the crowd in defiance.

Trump's reaction:

In his first reaction after the shooting at his rally, the 78-year-old Republican presidential candidate said in a statement he "was shot with a bullet that 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, who was not seriously injured, said on his Truth Social site.

He is currently doing "fine" and being checked at a medical facility, said reports.

The former President is "fine and is being checked out at a local medical facility," Trump Communications Director Steven Cheung said in a statement following the attack.

US leaders react:

US President Joe Biden condemned the assassination attempt on his rival election candidate Donald Trump.

Political leaders on both parties slammed the attack minutes after the Republican candidate was rushed off stage by the Secret Service with blood running down his face.

"There's no place in America for this kind of violence. It's sick. It's sick. It's one of the reasons why we have to unite this country... We cannot be like this, we cannot condone this," Biden told reporters in an emergency briefing at Rehoboth Beach in Delaware.

"The idea that there's political violence, or violence in America like this, is just unheard of. It's just not appropriate. Everybody, everybody must condemn it. Everybody," Biden said.

Vice President Kamala Harris said on X: "We are praying for him, his family, and all those who have been injured and impacted by this senseless shooting."

Biden's former boss, Barack Obama, in a statement, said there was "absolutely no place for political violence in our democracy."

"Although we don't yet know exactly what happened, we should all be relieved that former President Trump wasn't seriously hurt, and use this moment to recommit ourselves to civility and respect in our politics," the Democrat said on X.

Former president George W. Bush condemned the "cowardly" attack.

"Laura and I are grateful that President Trump is safe following the cowardly attack on his life. And we commend the men and women of the Secret Service for their speedy response," the Republican said in a statement.

The shooter had been "tentatively identified," police said, and was believed to be working alone.

The US Secret Service said in a statement that the suspected shooter "fired multiple shots toward the stage from an elevated position outside the rally" before being "neutralized" by agents.

Police confirmed that a male spectator was killed and two critically injured, all of them male adults.

The attack sent shock waves around the world prompting leaders of India, Britain, Israel, Japan, and a host of other countries to express outrage.

It has also triggered political storms, with some Republicans pointing the finger at Biden and right-wing conspiracy theories flooding social media.