Barack Obama
Barack ObamaReuters

President Barack Obama on Tuesday called on Republican presidential candidate Donald Trump to “stop whining”, following Trump's claims that the presidential election was rigged.

"You start whining before the game's even over?" Obama said during a news conference in the White House Rose Garden, according to CNN.

He added that Trump's claim is "not based on facts."

Trump and his associates have increasingly claimed the U.S. election system is "rigged," and the Republican candidate has urged his supporters to monitor polling sites for potentially ineligible voters attempting to cast ballots.

The remarks, however, have been brushed off even by Republican governors, who say there are no signs of corruption in their states' voting systems.

Obama echoed those sentiments Tuesday, saying there's "no serious person out there who would suggest somehow that you could even rig America's elections."

He further claimed Trump's warnings could abrade faith in the U.S. political system.

"One way of weakening America and making it less great is if you start betraying those basic American traditions that have been bipartisan and have helped to hold together this Democracy now for well over two centuries," Obama said, according to CNN.

He derided Trump's remarks as reflective of an unpresidential attitude, declaring again that the Republican nominee's temperament was disqualifying.

"It doesn't really show the kind of leadership and toughness that you'd want out of a president. You start whining before the game's even over? If whenever things are going badly for you and you lose you start blaming somebody else? Then you don't have what it takes to be in this job," Obama was quoted as having said.

He said the warnings of a "rigged election" are entirely unprecedented in modern American political history.

"I have never seen in my lifetime or in modern political history any presidential candidate trying to discredit the elections and the election process before votes have even taken place. It's unprecedented," Obama said.

"I'd advise Mr. Trump to stop whining and go try to make his case to get votes," Obama continued, adding, "And if he got the most votes, then it would be my expectation of Hillary Clinton to offer a gracious concession speech and pledge to work with him in order to make sure that the American people benefit from an effective government, and it would be my job to welcome Mr. Trump, regardless of what he said about me, or my differences with him on my opinions, and escort him over to the Capitol, in which there would about peaceful transfer of power."

"That's what Americans do," the president said.

Trump's comments come as he suffers a decline in polls after a 2005 video of Trump making lewd comments about women surfaced, and following allegations by women of sexual harassment which he has denied.

His comments that the system was rigged followed the latest polls, one of which found Clinton had a double digit lead.