Donald Trump 'fine' after being whisked off stage as gunshots heard

Former US president Donald Trump is "fine" after he was whisked off stage by Secret Service agents after gunshots were heard during a rally in Pennsylvania on Saturday, his campaign said.

"President Trump 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. More details will follow," Trump spokesman Steven Cheung said in a statement.

Videos from the scene showed Trump lifting his fist as he was escorted off stage with a bloody ear.

Trump had only just begun his speech in the town of Butler when the incident occurred. TV footage showed panic breaking out in the front ranks of the rally after a series of loud bangs.

US Secret Service spokesman Anthony Guglielmi said an "incident" had occurred during the rally.

"The Secret Service has implemented protective measures and the former President is safe. This is now an active Secret Service investigation and further information will be released when available," he wrote on social media platform X.

Trump is campaigning to return to the White House in November's presidential election against President Joe Biden.

Biden and Vice President Kamala Harris had been briefed on Saturday's incident, the White House said.

"I’m grateful to hear that he’s safe and doing well. I’m praying for him and his family and for all those who were at the rally, as we await further information," Biden said in a statement.

"There’s no place for this kind of violence in America. We must unite as one nation to condemn it."

Former US president Barack Obama said there was "absolutely no place for political violence in our democracy," in a post on X.

"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 Republican speaker of the House Mike Johnson said he had also been briefed about the incident.

"This horrific act of political violence at a peaceful campaign rally has no place in this country and should be unanimously and forcefully condemned," he wrote on X.

The Republican National Convention, where Trump is set to be officially nominated as the party's candidate for the presidential election, is due to begin in Milwaukee, Wisconsin on Monday.