Donald Trump described on Thursday how he narrowly survived an attempt on his life, telling a rapt audience at the Republican National Convention in his first speech since the attack that he was only there "by the grace of Almighty God."

"I heard a loud whizzing sound and felt something hit me really, really hard on my right ear," he said in Milwaukee, a thick bandage still covering his ear. "I said to myself, 'Wow, what was that? It can only be a bullet.'"

When he told the crowd that he was "not supposed to be here," the delegates chanted back, "Yes you are!" With photos of a bloodied Trump showing on screens behind him, Trump praised the Secret Service agents that rushed to his side and paid tribute to the volunteer firefighter who was killed, Corey Comperatore, kissing his fire helmet.