“I think Secretary of State Pompeo, the intelligence services, the foreign countries that are working with us have it about right that ISIS is not defeated. We have got to keep the pressure on ISIS so they don’t recover,” Mattis said in an interview on NBC News’ “Meet the Press” set to air Sunday.

Mattis’ warning comes after Trump announced last week that the U.S. will move special operation teams away from the Syrian border as Turkey launches an offensive against Kurdish forces. The Kurds have long fought alongside the U.S. against the Islamic State in the region.

“You can pull your troops out, as President Obama learned the hard way, out of Iraq but the ‘enemy gets the vote’ as we say in the military. And in this case, if we don’t keep the pressure on then ISIS will resurge. It’s, it’s absolutely a given that they will come back,” Mattis continued.