[NEW YORK] Hillary Clinton has widened her lead over Donald Trump nationally and in key swing states three weeks before Election Day, a poll showed Monday, as the Republican presidential nominee struggled to find a way back into the race.
Mr Trump, whose campaign has been reeling in the face of lewd comments about women and accusations of sexual assault, has doubled down on claims of "large scale voter fraud" in the US election, despite denials from within his own party.
And his team has deployed his wife Melania in a media blitz to try to tamp down the furore over the allegations, with interviews set to air late Monday on CNN and early Tuesday on Fox News.
"Those words, they were offensive to me and they were inappropriate. And he apologised to me. And I accept his apology. And we are moving on," Mr Trump told Fox, in an excerpt released by the network.
The Republican nominee takes the stage Wednesday with his Democratic rival Hillary Clinton in their final debate before voters make their choice on Nov 8.
Mrs Clinton leads Mr Trump by 12 points - 50 per cent to 38 per cent - among likely voters nationwide, in a four-way contest with third-party candidates, a poll by Monmouth University showed. Among registered voters, her lead is 11 points.
Meanwhile, a survey from Quinnipiac University showed Mrs Clinton leading in several key battleground states - Colorado, Florida and Pennsylvania - and even with Mr Trump in Ohio.
A CNN poll puts Mr Trump ahead by four points in Ohio, but gives Mrs Clinton a slight lead in North Carolina and Nevada.
Her leads in key states corresponds to her advantage of 6.4 percentage points in an average of recent national polls given by RealClearPolitics.
The polls indicate that the allegations swirling around Mr Trump have taken their toll. Monmouth University found that six in 10 voters believe he made unwanted sexual advances towards women - claims he vehemently denies.
Mr Trump, who was headed to Wisconsin for a rally, is scheduled to hold two events Tuesday in Colorado.
After the first debate, Mr Trump said he would respect the election result. But he backtracked in an interview with The New York Times last month, saying, "We're going to see what happens."
And since then, he has unleashed a litany of complaints about the nation's election system, and also blamed the media for his woes, raising concerns about possible unrest should he lose.
"Of course there is large scale voter fraud happening on and before election day," Mr Trump wrote on Twitter, without offering corroborating evidence.
"Why do Republican leaders deny what is going on? So naive!" Mr Trump's running mate Mike Pence sought to ease tensions, insisting his camp would accept defeat if voters reject the Republican ticket at the polls.
"We will absolutely accept the results of the election," he told CBS Sunday.
Ohio Secretary of State Jon Husted, a Republican who oversees election operations in his state, insisted Monday that Mr Trump was being "irresponsible" for warning of voter fraud.
"If there is a systemic problem, please identify it. Don't just make an allegation on Twitter. Tell me," Mr Husted said on CNN.
For Mrs Clinton's campaign manager Robby Mook, Mr Trump is "desperately trying to shift attention from his own disastrous campaign."
"He knows he's losing and he's trying to blame that on the system. This is what losers do," Mr Mook said during a press call on Monday.
But Mr Trump's warnings may be having an impact.
A new poll by Politico and Morning Consult reveals that some 41 per cent of voters believe the election could be "stolen" from Mr Trump through massive voter fraud.
More than seven in 10 Republicans believe the election could be taken from them, while 17 per cent of Democrats agree with the potential for serious ballot box fraud.
The poll of 1,999 registered voters was conducted Oct 13-15.
The nation's top elected Republican, House Speaker Paul Ryan, who has declared that he would no longer "defend" the party's nominee, rebuked Mr Trump over his comments questioning the validity of the election process.
Mr Ryan is "fully confident the states will carry out this election with integrity," his spokeswoman AshLee Strong said.
Mrs Clinton is lying low ahead of the final debate, apparently relying on Trump self-destructing.
"She is trying to avoid issues for the next 22 days in the hopes that this will just end up being about Mr Trump," his campaign manager Kellyanne Conway told CNN Monday outside of Trump Tower in New York.