Texas Gov. Rick Perry (R) said Thursday that there was "a very real possibility" that terrorists from the Islamic State of Iraq and the Levant has crossed into the U.S. through the Southern border with Mexico.

Perry was asked about the possibility following a speech he delivered at the conservative Heritage Foundation in which he criticized the Obama administration's handling of the border crisis and called for an expanded air campaign against ISIL in Iraq and Syria. He noted that there was "no clear evidence" of terrorist crossings but that the porous border made it impossible to know who exactly was coming into the U.S, according to The New York Times.

I think there is the obvious, great concern that — because of the condition of the border from the standpoint of not being secure and us not knowing who is penetrating across — that individuals from ISIS or other terrorist states could be."

Border hawks have long warned that enemies of the U.S. or any number of nefarious characters could be sneaking in through Mexico, and Perry gave another example on Thursday: He said three Ukrainians had been apprehended near the border in Texas in the last 60 days, Business Insider reported.

Perry's speech came less than a week after he was indicted for abuse of power in Texas.