The FBI has identified the man they believe attempted to assassinate Donald Trump on Saturday

The FBI said in a statement: "The FBI has identified Thomas Matthew Crooks, 20, of Bethel Park, Pennsylvania, as the subject involved in the assassination attempt of former President Donald Trump on July 13, in Butler, Pennsylvania.

"This remains an active and ongoing investigation, and anyone with information that may assist with the investigation is encouraged to submit photos or videos online at FBI.gov/butler or call 1-800-CALL-FBI."

CNN had earlier reported the man the authorities believed to be responsible was a registered Republican, who had previously made a small contribution to the Progressive Turnout Project, a Democratic-aligned group.

Meanwhile, the former president's campaign managers have promised the Republican National Convention will continue as planned "where we will nominate our President to be the brave and fearless nominee of our Party."

However, they will be employing additional security measures for the event in Milwaukee.

Susie Wiles and Chris LaCivita told staffers in a memo they "remain horrified" by what happened.

They added: "[We] hope that this horrendous act will bring our team, and indeed the nation, together in unity and we must renew our commitment safety and peace for our country.

"We condemn all forms of violence, and will not tolerate dangerous rhetoric on social media.

"In moments of tragedy and horror, we must be resolute in our mission to reelect President Trump."

Trump is now out of hospital and has returned to New Jersey.

He earlier broke his silence on what happened with a post on his Truth Social platform.

He said: "I was shot with a bullet that pierced the upper part of my right ear.

"I knew immediately that something was wrong in that I heard a whizzing sound, shots, and immediately felt the bullet ripping through the skin. Much bleeding took place, so I realised then what was happening."

The former 'Apprentice' star confirmed the shooter had been killed and also offered his condolences to the family of a person who lost their life during the shocking incident as he thanked the United States Secret Service, and law enforcement officials.

He wrote: "I want to thank the United States Secret Service, and all of law enforcement, for their rapid response on the shooting that just took place in Butler, Pennsylvania.

"Most importantly, I want to extend my condolences to the family of the person at the rally who was killed, and also to the family of another person that was badly injured.

"It is incredible that such an act can take place in our country.

"Nothing is known at this time about the shooter, who is now dead."