Hillary Clinton has attacked Donald Trump as a threat to democracy, as their bitter battle for the US presidency continues.
"We know the difference between leadership and dictatorship, and the peaceful transition of power is one of the things that sets us apart," she told crowds in Cleveland on Friday (local time).
Mr Trump has come under heavy criticism from the Clinton campaign for refusing to say if he'd accept the results of the US election if he didn't win.
"Donald Trump refused to say that he'd respect the results of this election. By doing that, he's threatening our democracy," Ms Clinton told her supporters.
She has also released hard-hitting ads featuring Khizr Khan, whose son died serving the US in Iraq.
"In 2004, my son was stationed in Iraq. He saw a suicide bomber approaching his camp. My son moved forward to stop the bomber when the bomb exploded. He saved everyone in his unit. Only one American soldier died," Mr Khan says in the video.
"My son was Captain Humayun Khan. He was 27 years old and he was Muslim American."
A visibly upset Mr Khan then asks Mr Trump: "Would my son have a place in your America?"