Donald Trump said he was at the Republican National Convention 'by the grace of Almighty God' following Saturday's attempted assassination, as he accepted the party's presidential nomination at the conclusion of the four-day event on Thursday.

"I'm not supposed to be here tonight," he told them, before the crowd began chanting: "yes you are!"

"Thank you but I'm not and I'll tell you, I stand before you in this arena only by the grace of Almighty God," he said.

Trump also described the moments of the shooting itself but promised "you'll never hear it from me a second time because it's actually too painful to tell."

"The assassin's bullet came within a quarter of an inch of taking my life," he said. "I started to like this turn to my right and was ready to begin a little bit further turn which I'm very lucky I didn't do when I heard a loud whizzing sound and felt something hit me really really hard on my right ear."

He added that he realised it was a bullet, touched his ear and found his hand 'covered with blood'.

"I immediately knew it was very serious, that we were under attack and in one movement proceeded to drop to the ground. Bullets were continuing to fly as very brave Secret Service agents rushed to the stage," he continued.

Trump was also seen kissing the helmet of fire chief Corey Comperatore, who lost his life on Saturday. His speech concludes the RNC, while the Democratic convention is scheduled for next month.