The attack on Donald Trump at his campaign rally in Pennsylvania has put the spotlight on the apparent security lapse and some are also pointing fingers at the Secret Service for letting an attacker slip by.
The former president himself did thank the Secret Service and other law enforcement "for their rapid response on the shooting that just took place".
But questions are being raised and some are calling it a “complete failure” on the part of the Secret Service.
US House Speaker Speaker Mike Johnson vowed that the House will conduct a full investigation.
In a post on X, formerly Twitter, the speaker said: "The American people deserve to know the truth.
"We will have Secret Service Director Kimberly Cheatle and other appropriate officials from DHS and the FBI appear for a hearing before our committees ASAP."
The Secret Service has agreed to brief the House Oversight Committee about the attack, a spokesperson confirmed to The Hill.
"He (Trump) does get a very robust former protection detail that is with him all the time. But he doesn't necessarily get all of the different assets that are available. So, I think that there are some aspects of this incident that are going to be investigated," retired Secret Service Supervisor Bobby McDonald told Reuters.
“The Secret Service will now look at what happened and how that they can again develop and continue to enhance their protective methodologies to make sure that things like this do not happen in the future.
At the start of the press conference, FBI field officer Kevin Rojek confirmed that the incident was being treated as an assassination attempt.
"This evening we had what we're calling an assassination attempt on our former president Donald J Trump," he said.
"It's still an active crime scene," he added, pointing out that they had a number of agents on the scene investigating the incident.
During the news conference, the FBI said law enforcement did not know there was a person on the roof of a building nearby Donald Trump's rally until shots were fired.
All three victims from the rally - two who were wounded and one who was killed - are adult males, law enforcement says.
Many of the questions at this news conference specifically about the response to the gunman and whether it was quick enough are being batted away as questions for the US Secret Service.
The FBI special agent speaking here, Kevin Rojek, says that the Secret Service were not able to be part of this news conference.
Law enforcement say they could release the name of a suspected shooter within the next few hours.
Lt. Col George Bivens from the Pennsylvania State Police said officers at the scene had acted "heroically" to respond to the shooter.
He says there is no reason to believe there is any further "existing threat out there".
The FBI says they are not prepared to identify the attacker and they have not yet identified a motive.
The attacker was not carrying any ID documents, so officials are waiting for DNA and biometric data to make an identification, law enforcement says.
Donald Trump has left the area his rally was held in Butler under the protection of the Secret Service, according to a statement by Pennsylvania Governor Josh Shapiro posted on X.
Shapiro said he was thankful that Trump was fine and wished him a full and speedy recovery. He added that he was "grateful for all law enforcement who responded, protected the former president, and worked to bring the situation under control".
He confirmed that federal law enforcement officials would continue to lead on the investigation into the shooting of Trump, while Pennsylvania State Police would lead the investigation into the shooting of the other victims.
"I respectfully ask that we treat our fellow Americans with respect and join together to universally condemn the unacceptable violence we witnessed earlier today in Butler," he added.
President Joe Biden appeared on camera to condemn the attack and later spoke to his November election rival
BBC
