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".
Donald Trump dominated discussion on Twitter during the third and final presidential debate with Hillary Clinton.
Figures released by Twitter showed that 59% of conversation about the two candidates related to the Republican billionaire.
The top tweeted moments of the debate were Trump and Clinton discussing the treatment of women and Trump refusing to say he will accept the election results.
A discussion about Russia and nuclear weapons, with Mrs Clinton calling Mr Trump a "puppet" of Russian president Vladimir Putin, also featured prominently.
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."