Secret Service agents quickly escorted former President Donald Trump off stage after what sounded like gunshots were heard at a rally in Pennsylvania.
The footage shows him grimacing and raising his hand to his right ear before ducking as sharp bangs – apparently gunshots – are heard.
He was quickly surrounded by Secret Service agents and rushed off stage to a waiting car. He raised his fist as he was ushered into the vehicle.
In a statement, Trump’s campaign said he was “fine” and was being “examined” at a local medical facility.
“President Trump thanks law enforcement and first responders for their swift action in this brutal act,” spokesman Steven Cheung said.
The former president appeared to have blood coming from his ears as security guards led him away.
Law enforcement sources later told US media that the male suspect and a bystander were dead.
In a statement, the Secret Service said Trump was safe and that measures were being taken to protect him.
They added that an investigation is underway and further details will be released as they become available.
The Republican presidential candidate had just begun speaking to his supporters in Butler, Pennsylvania – a key swing state in November’s election – when shots rang out.
Loud explosions rang out as Trump spoke about his successor, President Joe Biden, and his administration.
Several supporters holding signs and standing behind Trump ducked when they heard the gunshots.
Witnesses who spoke to the BBC said the gunfire may have come from a single-storey building to the right of the stage where Trump was speaking.
One witness – Greg – told the BBC he spotted a suspicious-looking person “crawling like a bear” on the roof of the building about five minutes before Trump took to the stage. He said he pointed the person out to police.
“He had a rifle, we could clearly see he was holding a rifle,” he said. “We were pointing at him, the police were running around on the ground – we were like ‘hey man, there’s a guy on the roof with a rifle’ and the police didn’t know what was going on.”
Another witness, Jason, told the BBC he heard five gunshots in quick succession.
“We saw Secret Service rushing at Trump to protect him. Everyone in the crowd got down very quickly,” he said.
“Right after that, he stood up, raised his fist in the air and said a few things.”
Tim – who was also at the protest – told the BBC he heard “a bunch” of gunshots.
“There was a jet of water coming out that we thought was a fire hose at first, then the speaker on the right side started falling,” he said.
“Something hit the hydraulic line. [which caused it to fall]. We saw President Trump fall to the ground and people started lying on the ground because of the chaos.”
In a written statement, President Biden said he was “grateful to hear” that Trump was “safe and well.”
“There is no place for this kind of violence in America,” he added. “We must stand together as a nation to condemn it.”
Politicians from both parties joined Mr Biden in condemning the apparent attack.
Former President Barack Obama said there was “absolutely no place for political violence in our democracy” and he was “relieved that former President Trump was not seriously injured”.
Trump’s Vice President Mike Pence said he and his wife were praying for their former ally, and called on “every American to join us.”
“My thoughts and prayers are with former President Trump. I am grateful for the decisive response of law enforcement. America is a democracy. Any form of political violence is never acceptable,” House Minority Leader Hakeem Jeffries said in a statement.
Trump is set to accept his party’s presidential nomination at the convention in Milwaukee on Monday. Some have speculated that he is set to unveil his running mate at the rally in Butler.
He remains in a tight race with President Biden for re-election in 2020.
