Republican presidential candidate Donald Trump has said he will accept the result of the US election "if I win".
But he added he reserved the right to file a legal challenge.
His comments came after he refused to promise during the final presidential debate in Las Vegas that he would trust the outcome on November 8th if he loses.
The Republican nominee had told the audience he would keep them "in suspense".
The third and final presidential debate between Donald Trump and Hillary Clinton began without a handshake.
After Fox News host Chris Wallace introduced the two candidates, both Trump and Clinton walked to their podiums without shaking hands - and barely acknowledging each other.
Taking place in Las Vegas, the debate is the final head-to-head clash between Trump and Clinton before the US presidential election on November 8.
Donald Trump has refused to say if he would accept the result of the election if he loses, but could he challenge it and what would happen?
During the debate Trump said "bad hombres" needed removing from the US and branded Clinton a "nasty woman". Both sparked jokes on Twitter.
The Republican refused to say whether he will accept the result of the presidential election, saying: "I will look at it at the time."