Republican Donald Trump has refused to commit to accepting the election result if he loses, in the final TV debate against Hillary Clinton.



"I will tell you at the time," he told moderator Chris Wallace. For days he has claimed the election is "rigged".



The Las Vegas debate continued the campaign's bitter tone, with Mr Trump calling Mrs Clinton a "nasty woman".



Polls show Mr Trump is losing in key battleground states after facing a slew of sexual assault allegations.



Most Americans will cast their votes on 8 November.



Other highlights from the debate at the University of Nevada, include:

• Mrs Clinton vowed to uphold women's and LGBT rights, while Mr Trump pledged to protect gun rights

 

• Mr Trump said he expects a key ruling that made abortion legal in the US to be overturned if president

 

• Clinton says Mr Putin wants Mr Trump elected because he wants a puppet as US president

 

• "I don't know Putin. He said nice things about me," Mr Trump responded

 

• He says he will build a wall on the southern border

 

• "We have some bad hombres and we are going to get them out," he said

When asked about her paid speech to a Brazilian bank in which she spoke of her dream of open trade and open borders, Mrs Clinton said she was talking about energy policy.



In one key exchange, he attacked her 30 years of "very bad experience" and she responded by going through her timeline, comparing where she was to where Trump was.



While she was in the Situation Room helping to take out Osama Bin Laden, "he was hosting the Celebrity Apprentice", she said.