Donald Trump. John Moore/Getty Images A top spokesman for Hillary Clinton said Tuesday morning that Donald Trump's assertion the election would be "rigged" against him was "dangerous" rhetoric.

"Even for a reflexive conspiracy theorist like Trump, this is pathetic," Clinton campaign spokesman Brian Fallon wrote on Twitter. "It's dangerous, too."

Trump made the outlandish claim about the election being cooked against him twice on Monday — first at a rally in Columbus, Ohio, and later on Fox News host Sean Hannity's program.

During the rally, Trump told the crowd he wanted to "be honest" with them while discussing the election outlook.

"I think my side was rigged," he said. "If I didn't win by massive landslides ... I hear more and more that the election on November 8, can you believe, we're almost there."

Then on Hannity's program, Trump said he had "been hearing" for "a long time" that the fall election could be rigged.

"And I know last time, there were — you had precincts where there were practically nobody voting for the Republican," the New York businessman said of the 2012 election. "And I think that's wrong. I think that was unfair, frankly, than Mitt Romney.

"You had areas where a lot of people were curious — how is that possible?" he continued. "And I've been hearing about it for a long time. And I just hope that there's really, I hope the Republicans get out there and watch very closely, because I think we're going to win this election, but if it's rigged, like anything else, look, it was rigged, I thought, a little bit for me, and we won in landslides."

The Republican nominee told Republicans to "be careful" or the election would be "taken away from us."

"And I'm telling you, November 8, we'd better be careful, because that election is going to be rigged," he said. "And I hope the Republicans are watching closely or it's going to be taken away from us."

Trump would be the first presidential candidate in modern times, possibly ever, to blame an election loss on voter fraud or a rigged election.

The Republican nominee has lamented about a "rigged" process earlier in the election cycle, chastising the process for selecting delegates after Sen. Ted Cruz won the majority of the Colorado delegates.

He is trailing Clinton by 4.4 percentage points in the RealClearPolitics average of several polls.