Former Defense Secretary James Mattis is warning President Donald Trump’s decision to pull out U.S. troops from Syria’s border could have dire consequences — including the resurgence of ISIS.

In an interview aired Sunday on NBC News’ “Meet The Press,” a clip of which was released beforehand, Mattis said the United States has to “keep the pressure on ISIS so they don't recover.”

"We may want a war over; we may even declare it over,” he said.

“You can pull your troops out as President [Barack] Obama learned the hard way out of Iraq, but the 'enemy gets the vote', we say in the military. 

“And in this case, if we don't keep the pressure on, then ISIS will resurge. It's absolutely a given that they will come back."

Mattis added there’s no predicting if the Syrian Kurds will be able to fend off the attacks by Turkey, calling it “a situation of disarray right now.”

"Obviously, the Kurds are adapting to the Turkish attacks,” he said. “And we'll have to see if they're able to maintain the fight against ISIS. It's going to have an impact. The question is, how much?"

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