Hillary Clinton says there could be "tremendous consequences" from Donald Trump's comments that there may be something Second Amendment supporters "can do" to stop her.

Clinton says the remark was a "casual inciting of violence" that shows he lacks the temperament to be commander-in-chief. The comments, Clinton says, were the latest in a long string by Trump that "crossed the line" and raises the stakes for the 2016 campaign.

She says that words matter and "if you are running to be president or you are president of the United States words can have tremendous consequences."

Trump insists he never advocated violence and his comments Tuesday have been manipulated for political purposes.

Clinton is speaking at a campaign rally in Des Moines.