WASHINGTON -  Donald Trump, the Republican presidential candidate, has refused to commit to accepting the Nov 8 election result if he loses, in the final TV debate against Hillary Clinton, his Democratic rival.

"I will look at it at the time. I'm not looking at anything now," Trump said on Wednesday night in the city of Las Vegas in Nevada.

"The media is so dishonest and so corrupt and the pile-on is so amazing, The New York Times wrote an article about it. They don’t even care, it's so dishonest, they’ve poisoned the minds of the voters, but unfortunately for them, I think the voters are seeing through it,” he added.

Trump said that Clinton "shouldn't have even been allowed to run" for the White House. "It’s crooked — she’s — she’s guilty of a very, very serious crime. She should not be allowed to run."

"And just in that respect, I say it’s rigged, because she should never…she should never have been allowed to run for the presidency based on what she did with emails and so many other things."

Clinton shot back at Trump, describing his stand as “horrifying”. She went on to assert that accepting the results of an election is fundamental to American democracy.

"This is how Donald thinks, it's funny, but it's really troubling. That is not the way our democracy works," Clinton stated. “He is denigrating. He is talking down our democracy. I am appalled," she said.

“I am appalled that someone who is the nominee of one of our two major parties would take that position,” continued Clinton, who according to leaked WikiLeaks emails, stole the Democratic nomination from Senator Bernie Sanders.

The whistleblowing website has published thousands of hacked emails belonging to the Democratic National Committee (DNC) and some of Clinton’s aides.

The emails revealed that the DNC undermined the primary campaign of Sanders and helped Clinton clinch the nomination.

Over the last week, Trump has intensified his criticism of the American electoral system. He called the election process rigged, and said the media is colluding with Clinton in order to beat him.

He has strongly questioned the legitimacy of the US elections, saying that he believed the vote was already being "rigged" at many polling places.

According to a new poll released on Monday, 41 percent of American voters are saying the 2016 election could be "stolen" from Trump due to widespread voter fraud.

And 73 percent of Republican voters think the election could be stolen from the billionaire businessman, while 17 percent of Democrats agree with the prospect of rigging.

On Sunday night, Trump's campaign manager said the Republican nominee would accept the result of the election because he will defeat Clinton next month. "Donald Trump will accept the results of the election because he will win the election, so they’ll be easy to accept,” Kellyanne Conway told CNN following the final debate.

The candidates declined to shake hands before and after the political sparring, setting the tone for what would later become yet another debate marked by shouting and interrupting.

Trump appealed to the Republican establishment by vowing to appoint Supreme Court justices with a "conservative bent" who would overturn a key ruling that made abortion legal in the US and protect gun rights.

He also stuck to his pledge to deport undocumented immigrants and secure US borders.

Meanwhile, Clinton firmly declared she would stand up for the LGBT community, defend abortion rights, focus on restoring the middle class and equal pay for women. "The government has no business in the decisions that women make," she said.

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

¬             Clinton says Russian President Vladimir Putin wants Trump elected because he wants a puppet as US president

¬             "You're the puppet!" Trump fired back, adding that Putin had "outsmarted" and "outplayed" the former secretary of state

¬             Clinton said Mr Trump "choked" when he met with Mexican President Enrique Pena Nieto about his plan to build the wall, but he insisted it would happen under his presidency

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

¬             Trump suggested Mrs Clinton and President Barack Obama coordinated the violence at his rally in Chicago earlier this year

When asked about her paid speech to a Brazilian bank in which she spoke of her dream of open trade and open borders, 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.

Trump has faced damaging fallout after a video emerged of him making obscene comments about groping women, with senior Republicans deserting him.

When pressed about sexual assault allegations made against him by several women in the wake of the video, Trump said the claims had been "largely debunked".

In addressing the groping accusations, Clinton said: "Donald thinks belittling women makes him bigger". “Nobody has more respect for women than I do," Trump said as the crowd was heard scoffing. He also blamed Clinton, whose campaign he said was responsible for drumming up the allegations. In recent days Mr Trump has railed against the election process itself, warning the vote is "absolutely rigged" with "large-scale voter fraud" taking place.