Pete Buttigieg said that President Trump’s decision to move U.S. troops out of northern Syria ahead of Turkey's planned attack on Kurdish allies has damaged the honor of U.S. soldiers.

Speaking on CNN’s State of the Union Sunday, the 37-year-old South Bend, Indiana, mayor said that he has spoken to soldiers on the campaign trail who are upset about Trump’s foreign policy decision. Buttigieg, a war veteran himself, said that the United States should stick by its allies, including the Kurds.

“The 21st century is going to be filled with these kinds of messy asymmetric conflicts, and we need to make sure the U.S. is in a position to defend our interests and to live up to our obligations to our allies. And right now, we’re seeing the reverse,” Buttigieg said.

“It is horrifying to see what is emerging, not just in terms of what is being done to Kurds, but in terms of ISIS fighters now being released, exactly as we were warned would happen. And we’re seeing the first reports of atrocities too,” he added.

Buttigieg said it was difficult to hear from soldiers who felt like they had betrayed the Kurdish people, who had helped fight back ISIS with them.

“What’s even more disturbing, to me as a veteran, is hearing from soldiers who feel that they have lost their honor over this. Who feel like they’re unable to look in the eye at allies who put their lives on the line to fight with us,” Buttigieg said. “And if you take away a soldier’s honor, you might as well go after their body armor next. That is what the commander in chief is doing right now.”

