Several Secret Service agents fired on a gunman in bushes near the property line of the West Palm Beach golf course after he was spotted a few hundred metres from where Trump was playing, law enforcement officials say.
The suspect left an AK-47-style assault rifle and other items at the scene and fled in a vehicle before he was later arrested.
A crime scene was set up at Trump International Golf Club in Florida after a gunman was disturbed. (AP PHOTO)
The apparent attempt on Trump's life came just two months after he was shot at a campaign rally in Pennsylvania, sustaining a minor injury to his right ear.
"I would like to thank everyone for your concern and well wishes - It was certainly an interesting day!," Trump said on social media, thanking Secret Service and police for keeping him safe.
The suspect was widely identified in US media as Ryan Wesley Routh, 58, of Hawaii.
Soon after the incident, Trump sent an email to his supporters, saying: "Nothing will slow me down. I will NEVER SURRENDER!"
Police say the gunman fled leaving backpacks and an assault rifle at Trump's golf course. (AP PHOTO)
President Joe Biden later said he had directed his team to ensure the Secret Service has the resources it needs to ensure Trump's safety, according to a statement released by the White House.
The suspect was an outspoken supporter of Ukraine, who travelled there after Russia's invasion in 2022 and told journalists he aimed to help recruit foreign fighters to Kyiv's cause, having been rejected as too old to volunteer.
"A lot of the other conflicts are grey but this conflict is definitely black and white. This is about good versus evil," Routh said in a video interview posted by Newsweek Romania in June 2022.
"If the governments will not send their official military, then we, civilians, have to pick up the torch," said Routh, who maintained a tent in central Kyiv with flags of countries whose citizens had died in the war.
Ukraine's International Legion of foreign volunteers told Reuters Routh had "never been part of, associated with, or linked to the International Legion in any capacity".
Presidential candidate Donald Trump says he won't give up after another apparent attempt on his life (AP PHOTO)
A legion official told CNN Routh had sent emails offering to recruit foreign volunteers, but Ukraine's military thought the American was "delusional".
Ukraine's President Volodymyr Zelenskiy said he was glad to hear Trump was safe, and there was no place for violence in politics anywhere.
In Moscow, Kremlin spokesman Dmitry Peskov appeared to link the attempt to Washington's support for Ukraine.
"It is not us who should be thinking, it is the US intelligence services who should be thinking. In any case, playing with fire has its consequences," Peskov said when asked about the attempted assassination.
Palm Beach County Sheriff Ric Bradshaw said a Secret Service agent protecting Trump had seen a rifle barrel poking out from bushes about 365 to 460m from the former president as they cleared holes of potential threats ahead of his play.
The suspect was arrested by police on the highway about 65km from Trump's golf course. (AP PHOTO)
Agents engaged the gunman, firing at least four rounds of ammunition about 1.30pm on Sunday local time.
The gunman then dropped his rifle and fled in a black Nissan car. The sheriff said a witness saw the gunman and managed to take photos of his car and licence plate before he escaped.
Sheriff's deputies in neighbouring Martin County apprehended the suspect about 65km from the golf course.
I have been briefed on reports of gunshots fired near former President Trump and his property in Florida, and I am glad he is safe. Violence has no place in America.— Vice President Kamala Harris (@VP) September 15, 2024
The White House said in a statement Biden and Vice President Kamala Harris had been briefed about the incident and were relieved to know he was safe.
On social media platform X in 2020, an account believed to be Routh's expressed support for Democratic US presidential candidate Bernie Sanders and mocked Biden as "sleepy Joe".
Earlier this year, Routh tagged Biden in a post on X: "@POTUS Your campaign should be called something like KADAF. Keep America democratic and free. Trumps should be MASA ...make Americans slaves again master. DEMOCRACY is on the ballot and we cannot lose."
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