US law enforcement officials are reassessing security arrangements after a gunman opened fire near the White House Correspondents' Association dinner, raising questions about how he was able to get so close to an event attended by US President Donald Trump, cabinet members, and lawmakers.

Two former Secret Service agents and three senior US officials told Reuters on Sunday that federal agents appeared to carry out their plan to protect the president effectively on Saturday night, stopping the alleged gunman before he reached the basement level of the Washington Hilton, where Trump was set to speak.

But the fact that some attendees could hear the shots fired at a Secret Service agent underscored vulnerabilities, the officials said, even after a pair of assassination attempts against Trump during the 2024 campaign had already prompted stronger measures around the president's security.

The Secret Service did not immediately respond to Reuters' request for comment.

The most obvious lesson from the incident, the former law enforcement officials said, is that security personnel may need to expand the protective perimeter around the president at large public venues, even if that leads to public inconvenience.

Some of the US officials noted the security perimeter at Trump's rallies is often much more expansive than the one that was established on Saturday night.

At Saturday's dinner, guests were required to pass through magnetometers, or metal detectors, to enter the ballroom, but needed only a ticket to access the hotel itself. Several people tried to enter using last year's ticket, according to a person with direct knowledge of the event's planning.

Officials said the California man who allegedly sprinted past security, armed with multiple weapons, appeared to circumvent even that basic step by checking in to the hotel in the days before the event.

Bill Gage, who served on the Secret Service's Counter Assault Team for six years and is now executive protection director for the SafeHaven Security Group, said post-incident reviews will likely focus at least in part on pushing the magnetometers farther out to expand the outer perimeter.

The Secret Service, Gage said, "is going to have to find a way to better secure large hotels that may inconvenience the hotel goers and the hotel."

He also said the Secret Service would need to do a better job coordinating the evacuation of other administration officials.

Several law enforcement bodies, from the US Marshals to the Diplomatic Security Service, spirited away attendees after the shooting, highlighting how the complex web of those charged with protecting different VIPs can lead to seemingly uncoordinated responses.

While Trump was whisked off stage just over 30 seconds after the last shots were fired, according to a video and audio analysis conducted by Reuters, it took at least 100 seconds for Health and Human Services Secretary Robert F. Kennedy Jr. to leave the room and around 150 seconds for Secretary of State Marco Rubio and Pentagon chief Pete Hegseth to exit.

Don Mihalek, a former senior Secret Service agent who has worked previous correspondents' dinners at the Washington Hilton, said securing the sprawling site has long posed challenges.

"I'm sure the service is going to go back and re-look at the set-up there, and probably push out the perimeter some more now, because of what happened," Mihalek said.

Trump himself said at an impromptu news conference late on Saturday that the Washington Hilton was "not a particularly secure building."

During the first assassination attempt against Trump, which took place at a campaign rally in Butler, Pennsylvania, in July 2024, law enforcement officials were criticized for failing to set an effective security perimeter. That omission allowed a gunman to get a clean line of sight at the then-candidate, who was clipped in the ear.

Among those who were critical of the event's security posture was the shooter himself, who mused in a written manifesto, first reported by the New York Post, about how lax security appeared to be.

"Like, I expected security cameras at every bend, bugged hotel rooms, armed agents every 10 feet, metal detectors out the wazoo," the California man wrote. "What I got (who knows, maybe they're pranking me!) is nothing."

Conservative influencers and officials, including acting Attorney General Todd Blanche, quickly took to X to say the incident showed why Trump should move ahead with the construction of a ballroom on White House grounds.

A federal judge ordered a halt to the ballroom's construction in late March, saying the project was unlawful without congressional approval, although a federal appeals court later stayed that injunction.

One of the US officials said he was anticipating a review of security around the president and his cabinet, and possibly some changes. A second US official noted that the security of some cabinet members had been increased when the Iran war began in February.