Former U.S. President Donald Trump was indeed hit by an assassin's bullet or a fragment of one, the FBI said Friday, putting to rest questions over the nature of the Republican candidate's wounding at a campaign rally this month.

"What struck former President Trump in the ear was a bullet, whether whole or fragmented into smaller pieces, fired from the deceased subject's rifle," the FBI said in a statement.

Trump's right ear was covered in blood on July 13 after he was injured during a campaign rally in Pennsylvania.