US Republican presidential candidate Donald Trump said Saturday he would hold more outdoor campaign rallies despite the attempt on his life earlier this month.

Trump received a graze to the right ear from the bullet or a fragment, the FBI said, in the shooting at an event in Butler, Pennsylvania on July 13. 

One audience member was killed and two other spectators were seriously injured in the shooting. The gunman was shot dead by a Secret Service sniper.

What did Trump say?

Trump wrote on his social media platform Truth Social that the Secret Service, which is responsible for protecting US leaders, election candidates and other top officials, has agreed to "substantially step up" its operations.

"They are very capable of doing so. No one can ever be allowed to stop or impede free speech or gathering!!!" he posted.

However, US media reports suggest the Secret Service has encouraged Trump's campaign to stop arranging outdoor rallies and has suggested large indoor arenas instead.

The motive for the attack has still not been established. 

Trump has not held an outdoor rally since 20-year-old gunman Thomas Matthew Crooks tried to kill him from a roof.

But on Friday, Trump vowed to return to the scene of the crime in Pennsylvania and hold a "big and beautiful rally." He did not disclose when it would take place.

Shake up at Secret Service

Secret Service Director Kimberly Cheatle this week acknowledged that the agency had failed in its mission of protecting high-profile politicians and stepped down from her position.

Cheatle told a congressional committee that authorities had known about a "suspicious individual" ahead of the shooting but were unable to track him down in time.

Trump has since played up the assassination attempt for his US election campaign, telling Republican Party supporters that he "took a bullet for democracy."

Together with his voice for vice president, JD Vance, Trump is due to hold a rally at an indoor stadium in Minnesota on Saturday.

Vice President Kamala Harris — who is on course to take the Democratic nomination — was set to attend a fundraising event in Massachusetts.

mm/wd (AFP, dpa)