During Thursday’s GOP debate, Sen. Marco Rubio (R-FL) alleged that the Islamic State was exploiting the immigration system and entering the U.S. as “doctors and engineers.”

The claim came when he was asked about the estimation that the failed 2013 comprehensive immigration legislation he sponsored would have increased green card holders by another 10 million.

“First and foremost, this issue has to be more than anything else about keeping America safe. And here’s why: There’s a radical jihadist group manipulating our immigration system, and not just green cards. They’re recruiting people that enter as doctors and engineers and even fiancees,” he said. “They understand the vulnerabilities we have on the Southern border, they’re looking to manipulate the visa waiver countries to get people into the United States.

It is unclear by that answer whether Rubio now opposes increases to legal immigration, such an expansion of the H1B visa program that is often used to bring in high-skilled workers like doctors and engineers.

“Whether it’s green cards or any other form of entry into America, when I’m president, if we do not know who you are or why you are coming, you are not going to get into the United States of America,” he said.