For a second time in just over two months, the FBI and the Secret Service are investigating what the authorities described as an attempted assassination of former President Donald J. Trump.

The latest incident happened on Sunday afternoon at Trump’s golf course in West Palm Beach, Florida, where Secret Service agents spotted a person concealed in the bushes and holding a rifle while Trump was golfing. The Secret Service shot at the man, law enforcement officials said. Trump, who was a few hundred yards away, was not injured, unlike in the previous attempt, when he was shot in the ear at a rally in Pennsylvania on July 13.

The suspect fled but was taken into custody during a traffic stop, and a rifle with a scope was recovered from the bushes. A US law enforcement official identified the man as Ryan Wesley Routh, 58, who has lived in Hawaii and Greensboro, North Carolina.

Trump thanked the Secret Service, law enforcement and Ric Bradshaw, the local sheriff, for keeping him safe. In a post on his social media website, Truth Social, he called their work outstanding.

Vice-President Kamala Harris said she was “deeply disturbed” by what the FBI has said it is investigating as an attempt on Trump’s life, and she condemned “political violence”. In a statement released by the White House on Sunday night, she also reinforced President Joe Biden’s pledge to “ensure the Secret Service has every resource” to do its mission.

Routh had expressed the desire to fight and die in Ukraine. Routh’s posts on X revealed a penchant for violent rhetoric in the weeks after Russia’s invasion of Ukraine in 2022. “I am willing to fly to Krakow and go to the border of Ukraine to volunteer and fight and die,” he wrote.

The Secret Service had significantly bolstered Trump’s protective detail after coming under intense criticism following an attempt on his life in Butler, Pennsylvania, on July 13. That beefed-up detail, which includes additional agents and enhanced on-the-ground intelligence, might have played a role in the outcome this weekend, current and former officials said.

Yet the fact that a gunman was able to get a semiautomatic rifle with a telescopic sight so close to the former President, roughly 280 to 450 feet away, underscored how many urgent problems exposed in Butler remained unresolved — and how difficult it is for the Secret Service to respond to an unpredictable and violent political environment.

As in Butler, the biggest issues in Trump’s protection seem to involve securing the protective perimeter of a targeted site, even one they know as well as Trump’s properties. The would-be shooter positioned himself in the bushes on the perimeter of the former President’s golf club in West Palm Beach. A Secret Service agent was one hole ahead of Trump on the course and spotted the barrel of a gun, prompting agents to open fire on the man, Sheriff Bradshaw said at a news conference on Sunday.

Bradshaw said that Trump — one of the most polarising figures in the world — still retains a protective detail that is smaller than the one given to a sitting President. That, he said, limits the protections that the Secret Service and its local partners can provide.

“At this level that he is at right now, he’s not the sitting President — if he was, we would have had this entire golf course surrounded,” Sheriff Bradshaw said.

“But because he’s not, the security is limited to the areas that the Secret Service deems possible,” he added, while praising the service’s fast response. “So I would imagine that the next time he comes at a golf course, there’ll probably be a little bit more people around the perimeter.”

Michael Matranga, a former Secret Service agent who protected President Barack Obama, said the agency should “seriously consider giving former President Trump the same or equal package as the President of the US” and called the incidents “unprecedented”.

Lawmakers lauded the actions of the agents, but they vowed to subject the agency’s leadership to intense questioning about the suspect’s ability to position himself near the former President.

“The facts about a second incident certainly warrant very close attention and scrutiny,” said Senator Richard Blumenthal, a Democrat from Connecticut and the chairman of the Senate subcommittee investigating the security failures at Butler. “Certainly a second serious incident, apparently involving an assault weapon, is deeply alarming and appalling,” he added.

Senator Lindsey Graham, the South Carolina Republican who is a close ally of Trump, said the Senate’s investigations into the security lapses in Butler cited mismanagement within the Department of Homeland Security, which oversees the Secret Service, as well as budget and morale issues.

“They’ve lost their focus,” he said. “They need more resources. These agents just work; they have no lives.”