COLUMBUS, Ohio — Donald Trump questioned the integrity of the upcoming presidential election, criticized Columbus' fire marshal for limiting his crowd size and told people in Ohio's capital that "everything's rusting and rotting" in the nation's former industrial centers.
By and large, the people loved it.
Hundreds were turned away from Monday's event at the Columbus Convention Center; capacity was limited to 1,000 people.
"They’ve all been turned away. You saw them — it's a disgrace. So that's for political reasons," Trump alleged.
The Columbus Division of Fire told ABC News Trump's campaign was aware of the venue's capacity when it booked the space last Friday.
At the start of his town hall meeting, Trump blasted President Barack Obama's foreign relations policy, saying the United States should get along with Russia. He also took time to reinforce his stance on how to best protect the country and create jobs.
"The people in Ohio, the people in the Rust Belt — and they call it the Rust Belt for a reason, because everything's rusting and rotting — you lost your jobs. They're moving to Mexico," Trump alleged.
RELATED: We got rid of the 'rust' a long time ago
Trump's main opponent, Democrat Hillary Clinton, also made stops through the so-called Rust Belt over the weekend, touting her message of better pay to boost the middle class. The visits are hardly surprising: Swing states Ohio and Pennsylvania figure large in any presidential candidate's game plan.
In Columbus, Mark Kelly found himself pulled toward Trump's message Monday.
"I was most impressed with his stance of keeping jobs in America, specifically let the states battle it out — that’s fine, but going out to foreign countries and that, obviously that is an issue," Kelly said.
Monday's appearance — Trump's second stop in Ohio in less than week — was his first since his latest controversy: At last week's Democratic National Convention, Khizr Khan, father of an American Army captain killed in Iraq, spoke out against Trump, saying, "You have sacrificed nothing and no one." Khan also referred to Trump's call to ban Muslims from the United States, saying his son would never have been able to come to America.
Trump loyalists weren't swayed.
"I really think that the Democratic Party pays the man to say the things he said against Trump," Judy Gibson said. "The son was a hero, but we have a lot of heroes."
Trump drew criticism questioning why Khan's wife, Ghazala, stood silently on stage during her husband's speech. She's said she finds it too painful to talk about her son.
"I think some things Donald needs to slow down on what he says, but other than that, people make mistakes," Navy veteran Scott Law said. "But I like Donald Trump, nobody is going to change my mind about that."
But Trump saved his most stunning comments for a forecast of the upcoming election, saying he fears it "is going to be rigged" — an unprecedented assertion by a modern presidential candidate.
Trump's extraordinary claim — one he did not back up with any immediate evidence — would, if it became more than just an offhand comment, seem to threaten the tradition of peacefully contested elections and challenge the very essence of a fair democratic process.
"I'm afraid the election is going to be rigged, I have to be honest," he told the crowd in Columbus. He added that he has been hearing "more and more" that the election may not be contested fairly, though he did not elaborate further.
Trump made the claim after first suggesting that the Democrats had fixed their primary system so Clinton could defeat Bernie Sanders. Trump has previously backed up that thought by pointing to hacked emails from the national party that appeared to indicate a preference for Clinton. Still, the former Secretary of State received 3.7 million more votes than Sanders nationwide and had established a clear lead in delegates by March 1.
The celebrity businessman — who has been known to dabble in conspiracy theories, including claims that President Barack Obama was not born in the United States and, more recently, that Sen. Ted Cruz's father was an associate of President John F. Kennedy's assassin — also claimed that the Republican nomination would have been stolen from him had he not won by significant margins.
He then asserted that November's general election may not be on the up-and-up.
Requests to Trump's campaign for additional explanation were not returned.
The statement could be an effort by Trump to lay the groundwork of an excuse if he goes on to lose the general election. But if he were to be defeated in November and then publicly declare that the election results were bogus, his claim could yield unpredictable reactions from his supporters and fellow Republicans.
Trump did not repeat his claim at an evening rally in Mechanicsburg, Pennsylvania. But he has not been shy of asserting that the electoral process has been "rigged."
It became a frequent catchphrase of his during a low-water mark of his primary campaign this spring, when forces allied with Republican rival Ted Cruz managed to pack state delegations with supporters of the Texas senator. Trump also asserted that the Republican Party had changed the delegate allocation in the Florida primary to favor a native candidate, like Jeb Bush or Marco Rubio, at Trump's expense.
In recent weeks, in an effort to woo angry Sanders supporters to his campaign, Trump has made the claim that the Democrats' process was also rigged. Monday night, Trump said Sanders "made a deal with the devil," and said of Clinton, "She's the devil."
The Clinton campaign declined to comment about Trump's remarks.