Clinton says does not think of responding to Trump anymore

"I debated him for four and a half hours. I do not even think about responding to him anymore," Clinton, 68, told reporters travelling with her in Pennsylvania.

"So he can say whatever he wants to. He can run his campaign the way he wants to. He can go off on tangents, he can go to Gettysburg and say he is gonna sue women you have made accusations against him," she said.

"As we are travelling in these last 17 days, we are going to be emphasising the importance of electing Democrats down the ballot," the former secretary of state said.

Clinton, who is leading in polls, claimed that she won the third presidential debate by defeating Trump, 70.

"Well, I will tell you that was the third and last time I will ever have to debate Donald Trump. I mean, think about this. I have now spent four and a half hours on stage with Donald, proving once again I have the stamina to be president and commander-in-chief," she told her supporters in Pittsburg.

"And after every one of those debates, people have said, How did you do that? And, really, you just have to be of good cheer when you find yourself in a situation like that. You are in front of 50, 60, 70, 80 million people. And so, no matter what he was saying, I just kept thinking of all the people I have met throughout this campaign," Clinton said.

The former first lady called Trump's recent refusal to commit to accept the results of the election unacceptable, saying "We know in our country the difference between leadership and dictatorship, right? The peaceful transition of power is one of those things that sets us apart. And whether you support me or you support my opponent, together we must show that we support American democracy".

Democratic vice presidential nominee Senator Tim Kaine slammed Trump for him praising authoritarian leaders, using Chinese steel and aluminium instead of American-made metals and attacking on the US military even though he paid no federal income taxes for years to support it.

Kaine also reflected on why Clinton's historic candidacy resonates with him personally, saying "I would not have gotten very far – in fact, I would not have gotten into my first office – without a whole lot of really amazing women who have lent me their strength along the way so that I could be the candidate... that is why I am just so proud to be a strong man supporting a strong woman who will be the next president of the US".