(AFP) - Donald Trump was the target of an apparent assassination attempt Sunday in Florida, the FBI said, with the Republican presidential candidate's campaign and law enforcement reporting he was safe and unharmed.

The US Secret Service confirmed one or more of its agents "opened fire on a gunman" located near the boundary of Trump's golf course, and that an "AK-47 style rifle" with a scope was recovered along with a GoPro video camera.

Amid the confrontation with the Secret Service, the suspect bolted out of the shrubbery he had been hiding in and escaped in a black car. A witness helped police identify the vehicle and authorities tracked it down.

"We have somebody in custody right now that is a potential suspect," Palm Beach County Sheriff Ric Bradshaw told a news conference.

Trump had been golfing at his course in West Palm Beach, Florida, not far from his Mar-a-Lago residence, when the would-be shooter was spotted in bushes one hole ahead of the former president, Bradshaw said.

"President Trump is safe following gunshots in his vicinity," his campaign spokesman Steven Cheung said in a statement, while Democratic presidential hopeful Kamala Harris expressed relief her political rival was out of danger.

Trump himself said in a website fundraising message: "Fear not! I am safe and well, and no one was hurt. Thank God!"

The unnerving incident appears to mark the second time in as many months that Trump has been the target of an assassination attempt. The former president was wounded in the ear on July 13 as he addressed an outdoor rally in Butler, Pennsylvania.

- Unsure if shot taken -

Authorities who addressed Sunday's news conference did not confirm whether a gunman actually fired a weapon in the direction of the former president, but said that shots were fired by the Secret Service.

"We are not sure right now if the individual was able to take a shot at our agents," said Rafael Barros, of the Secret Service.

The Federal Bureau of Investigation said it is "investigating what appears to be an attempted assassination of former President Trump."

Officials praised the quick action of the Secret Service, an agency that has been under intense scrutiny since its apparent failure to detect and stop a gunman from shooting at Trump in Pennsylvania.

Sheriff Bradshaw said Secret Service personnel in Trump's protective detail spotted "this rifle barrel sticking out of the fence and immediately engaged that individual, at which time the individual took off."

He estimated the suspect was set up 300 to 500 yards (275 to 455 meters) away, but "with a rifle and a scope like that, that's not a long distance."

Sheriff William Snyder of neighboring Martin County said on CNN that the potential suspect who was stopped and detained by law enforcement had "a relatively calm, flat affect. He was not displaying a lot of emotions."

- 'Relieved' -

Law enforcement was launching a sweeping investigation but as of Sunday afternoon there was no indication of the shooter's motive.

The incident came amid heightened tensions in the knife-edge presidential race, and concern for the safety of both candidates.

"There is no place for political violence or for any violence ever in our country," President Joe Biden said in a statement.

"I have directed my team to continue to ensure that Secret Service has every resource, capability and protective measure necessary to ensure the former president's continued safety."

Vice President Harris took to social media to say "I am glad he is safe."

Several Trump supporters and members of his inner circle, including his running mate J.D. Vance, offered their support and gratitude that tragedy was avoided.

"I'm glad President Trump is safe," Vance said on X. "I spoke to him before the news was public and he was, amazingly, in good spirits."

The Secret Service, tasked with protecting presidents, former presidents and other dignitaries, has faced criticism since the Pennsylvania shooting.

Kimberly Cheatle, the head of the agency, resigned amid the ensuing scrutiny, and at least five agents were placed on administrative leave.

Representative Elise Stefanik, the fourth-ranking US House Republican, thanked law enforcement for their actions Sunday but raised questions about the latest incident.

"We must ask ourselves how an assassin was allowed to get this close to President Trump again," she said in a statement.

"There continues to be a lack of answers for the horrific assassination attempt in Pennsylvania and we expect there to be a clear explanation of what happened today in Florida."

© Agence France-Presse