Speaking to Fox News on Tuesday, Donald Trump appeared to lay the foundation for contesting the results of the presidential election by referring to a handful of reports of voting machine errors as a widespread problem that might make it impossible for him to accept defeat.

“I have to look at what’s happening,” Trump said, when asked if he might contest the result. “I have to look at reports that are coming out. There are reports that, when people vote for Republicans, the entire ticket switches over to Democrats — you’ve seen that — it’s happening at various places today, it’s been reported.”

“In other words, the machines,” he continued, “you put down a Republican and it registers as a Democrat, and they’ve had a lot of complaints about that today.”

NBC News reported on Tuesday afternoon that 19 Trump supporters in six Pennsylvania counties had complained about touch-screen machines not letting them cast their votes. The Trump campaign is reportedly considering legal action to compel authorities in those counties to take the voting machines out of service and conduct the rest of the election on paper ballots.

As Sheera Frenkel of Buzzfeed reports, one incident, documented on video by a voter in Philadelphia, spread widely online, even though the voter said that he had, eventually, been able to cast his vote for Trump.

The voter explained in another tweet that the machine had to be reset to allow him to vote for Trump, which he did.

Trump’s comments to Fox, casting doubt on the integrity of the voting process as it took place, were unprecedented for a major party candidate in the United States.

Although Trump’s statement to Fox mixed together rumors and “reports,” election officials have been debunking many such claims. As the Toronto Star’s Washington correspondent Daniel Dale noted, three complaints about such machine error in a county outside Scranton, Pennsylvania — caught by voters themselves before the votes were recorded — were called unfounded by technicians.

In many cases, claims of machine error, discovered on confirmation screens that flash up before votes are recorded, have been attributed to errors made by voters.

After one rumor of voting machine error during early voting in Texas was shared hundreds of thousands of times on Facebook last month, Trump complained, without pointing to any evidence, that the problem was widespread.

A Texas election official said last month that after one reported incident of a machine not working properly, which was caught before the vote was registered, the voter was allowed to use a different machine and had no problems.

As the Atlanta Journal-Constitution reported, one voting machine in Georgia was taken offline after a voter said that it had failed to register his vote for Hillary Clinton, assigning it instead to Trump.

Update: After apparently regaining control of his Twitter account from aides, Trump used the social network to incorrectly report that officials in Utah, who confirmed problems with voting machines in one county, said there were “voting machine problems across entire country.”

As Jake Tapper of CNN explained, Trump’s error appeared to be writing “country” instead of “county,” which is “the difference of an ‘r,’ but kind of an important one.”