US President Joe Biden led the condemnation after his election rival Donald Trump was wounded in a shooting incident at a rally in Pennsylvania Saturday that also reportedly killed at least one bystander.

Political leaders on both sides of the aisle slammed the violence 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.

He said he hoped to speak with Trump "shortly."

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, echoed his words in a statement, saying 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.

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," he said in a statement.

"I am horrified by what happened at the Trump rally in Pennsylvania and relieved that former President Trump is safe. Political violence has no place in our country," US Senate Majority Leader Chuck Schumer, a Democrat, wrote on X.

Top Senate Republican Mitch McConnell also wrote on X: "Tonight, all Americans are grateful that President Trump appears to be fine after a despicable attack on a peaceful rally. Violence has no place in our politics."

"As one whose family has been the victim of political violence, I know firsthand that political violence of any kind has no place in our society," former House Speaker Nancy Pelosi, whose husband was attacked in a home invasion in 2022, wrote, also on X.

"I thank God that former President Trump is safe. As we learn more details about this horrifying incident, let us pray that all those in attendance at the former President's rally today are unharmed," she continued.

Tech billionaire Elon Musk said Saturday that he "fully" endorses Trump after the rally violence.

"I fully endorse President Trump and hope for his rapid recovery," Musk wrote on X, as he shared a video of Trump pumping his fist while being escorted away by Secret Service officials.