Washington, 15 Juny 2024 (dpa/MIA) — Security measures for the US Republican Party convention and for Donald Trump have been stepped up following the assassination attempt on the former president.

Planning for the security of the huge gathering in Milwaukee in the US state of Wisconsin has been "reviewed and strengthened" following the assassination attempt on Saturday, said the director of the Secret Service, Kimberly Cheatle, on Monday.

The agency is responsible for protecting the occupant of the White House and former presidents. It was criticized after the assassination attempt, when a gunman shot at Trump from a nearby rooftop during a campaign rally in Pennsylvania.

The plan for the security measures for the four-day party convention, which begins on Monday, is flexible and will be further adapted if necessary "to ensure the highest level of security for convention attendees, volunteers and the city of Milwaukee," Cheatle added in statement.

Trump is set to be officially declared the Republican candidate for the presidential election in November at the party convention.

In addition to the increased security measures already implemented for Trump in June, changes will also be made "to ensure his continued protection for the convention and the remainder of the campaign," the statement added. No details of the increased security measures were given.

"The Secret Service is tasked with the tremendous responsibility of protecting the current and former leaders of our democracy," Cheatle said. "It is a responsibility that I take incredibly seriously, and I am committed to fulfilling that mission."

US Homeland Security Secretary Alejandro Mayorkas promised an independent and thorough investigation to clarify how the attack could have happened.

"An incident like this cannot happen," Mayorkas told CNN on Monday. "When I say that something like this cannot happen, we are speaking of a failure."

Cheatle said that the Secret Service would work with all investigative authorities "to understand what happened, how it happened, and how we can prevent an incident like this from ever taking place again." It will also co-operate "fully" with an investigation ordered by US President Joe Biden and possible congressional investigations.