Republican nominee Donald Trump threw Democratic nominee Hillary Clinton a sarcastic remark during the final presidential debate Wednesday night regarding her plans to allow the U.S. to accept refugees from civil war in Syria. The conflict has forced 4.8 million Syrians to leave their country and led to an estimated 470,000 deaths over the past five-and-a-half years.

“She’s taking in tens of thousands of Syrian refugees who probably, in many cases — not probably — who are definitely, in many cases, ISIS-aligned, and we now have them in our country, and wait until you see — this is going to be the great Trojan horse — and wait until you see what happens in the coming years,” Trump said of the Islamic State group in Syria and Iraq. “Lots of luck, Hillary — thanks for doing a great job.”

Is the statement true, false or a mix of both? Read on for a full fact-check.

“She is taking in tens of thousands of Syrian refugees…” Assuming Trump meant to describe Clinton’s future proposals — she is not holding public office and therefore incapable of enacting asylum or immigration policies — Clinton’s campaign provides no clear answer for the claim. While the campaign site promises that she’ll “ensure refugees who seek asylum in the U.S. have a fair chance to tell their stories” and create a national Office of Immigrant Affairs to foster integration, it provides no quantitative information.

Clinton has, however, said President Barack Obama’s pledge to accept 10,000 was “a good start.” But the U.S. “has to do more,” she's said.

“I would like to see us move from what is a good start with 10,000 to 65,000, and begin immediately to put into place the mechanisms for vetting the people that we would take in,” she told CBS News’ John Dickerson in September. “Looking to really emphasize some of those who are most vulnerable, a lot of the persecuted religious minorities, including Christians, and some who have been brutalized, like the Yazidi women.”

So, yes, she would indeed be “taking in tens of thousands of Syrian refugees,” as Trump claimed. The next part of his statement is somewhat more dubious.

“… who are definitely, in many cases, ISIS-aligned, and we now have them in our country…” There are, indeed, Syrian refugees residing in the U.S. — 11,000 of them, in fact. But, according to the State Department, 80 percent of Syrian refugees in the U.S. are children.

And as Vox pointed out, using Donald Trump Jr.’s widely criticized Skittles bowl analogy, a report from the Cato Institute found that Americans’ chances of being killed by a terrorist attack caused by a refugee are around one in 3.64 billion. The U.S. murder rate, by comparison, was five per 100,000 people as of 2015, according to the FBI.

While the U.S. has admitted 784,000 total refugees since the country’s most significant terror attack on Sept. 11, 2001, only three of those refugees have been arrested for suspected terrorist activities, according to the Migration Policy Institute. Two of them were not planning an attack in the U.S. and the third person’s alleged plans were hardly credible.

Most terrorist attacks happen outside of Western countries, despite recent incidents in Paris, Orlando and Brussels dominating headlines over the past year. In January, an ISIS attack in an eastern Syrian village killed at least 300 people, for example, while a string of ISIS suicide bombings and car bomb attacks killed more than 120 near Syria’s coast over the summer. In this sense, Trump’s prediction of a “Trojan horse” of terrorists is false: The refugees are, with a statistically insignificant exception, fleeing violence, not bringing it.