In a spirited exchange between President Donald Trump and moderator Kristen Welker, Trump was pressed on immigration and a report that more than 500 children have been separated from their parents.

Trump's response immediately drew questions. 

"The U.S. can't locate the parents of more than 500 children who were separated from them. How will they be reunited?" Welker asked

President Trump then proceeded to respond with a strange reference.

"These children are brought here by coyotes and lots of bad people, cartels, and they used to use them to get into our country," he said.

"Coyote” is a term for human smugglers along the U.S.-Mexico border, though the term is rarely used.

Trump would later twice repeat the coyote comment.

Trump had made the comment about coyotes before.

“A nation without borders is not a nation at all,” Trump said in 2018. “Without borders, we have the reign of chaos, crime, and — believe it or not — coyotes.”

The report Welker was citing comes from lawyers tasked with locating immigrant families who were separated by the Trump administration. In a Tuesday court filing, the lawyers claim they can't reach the parents of 545 children.

In 2018, the Trump administration systematically separated thousands of children from their parents under a so-called "zero-tolerance policy" in which parents were sent to federal prison before going to court on charges of entering the US without authorization. Because children can't be sent to federal prison with their parents, the government separated them, listed them as unaccompanied minors, and transferred them to the custody of the Office of Refugee Resettlement, The Southern Poverty Law Center reported. 

Democratic nominee Joe Biden was quick to respond to Trump's confusing comment and said coyotes aren't bringing them over, "it's their parents."