And on Sunday, in an interview with NBC's "Meet The Press", he said the campaign will "accept the will of the American people, you bet".
It looks like the closer we get to Election Day, the more Democratic presidential nominee Hillary Clinton is expending her voting map. "That's where the sense of a rigged election goes here, Chuck". Republicans, and some Democrats, have harshly criticized her decision to do so, but the Federal Bureau of Investigation did not recommend anyone face criminal charges for her use of a private email address run on a personal server.
For weeks, WikiLeaks has released thousands of hacked emails from John Podesta, chairman of Clinton's presidential campaign. "They don't control the inner cities the way Democrats do".
Trump's comments carried echoes of Clinton's allegations of a "vast right-wing conspiracy" organized to raise similar allegations against her husband two decades ago.
"What happened, how did it happen, how do we prevent it from happening?"
Pence said he and Trump would respect the will of the voters.
The tweet was aimed at Republican leaders who in recent days have indirectly tried to soften Trump's claim.
The poll was conducted during one of the most tumultuous periods of Trump's candidacy, after the release of a video in which he spoke about taking sexual advantage of women and during a time when numerous women have accused him of sexual misconduct.
81 percent say that most supporters of Hillary Clinton and Donald Trump not only disagree over plans and policies, but also disagree on "basic facts".
The latest batch showed the campaign worrying whether Sen. Bernie Sanders and Chelsea Clinton will be in the traditional Republican stronghold this week as well. He apologised for the video but has denied each of the accusations. In Ohio, meanwhile, Clinton and Donald Trump were tied in the new poll.
Hillary Clinton is not going to steal the White House like Lyndon Johnson stole a Texas Senate seat in 1948.
Republican presidential nominee Donald Trump dug deeper in his efforts to cast doubt on the legitimacy of the USA election, saying on Twitter that he believes the results are being "rigged" at many polling places.
Adding to the polemic over Trump's fraud claims, top advisor Rudy Giuliani told CNN on Sunday - without offering evidence - that Democratic districts are known for counting the votes of dead people.
"We will absolutely accept the results of the election", he told CBS. "What he's talking about is that 80 percent to 85 percent of the media is against him".
Pence, at a campaign event last Tuesday, waved away a woman's call for a revolution if Clinton wins. "But the American people are exhausted of the obvious bias in the national media".
Trump's desire to not lose is now taking the form of blaming others for it.
And unlike Trump, Pence acknowledged Sunday that evidence points to Russian Federation being behind the hacking of Democratic emails. I think when most Americans hear that an election is rigged, they think of government action to rig the election.
After surmising that Clinton was getting "pumped up" ahead of Wednesday's debate rather than preparing for it, Trump told supporters: "I think we should take a drug test prior to the debate, 'cause I don't know what's going on with her". But Trump seemed to brush back against his vice presidential pick.