The Syrian regime appears to have weaponized chlorine again, Defense Secretary Jim Mattis said, but “we are even more concerned about the possibility of sarin use.” | Chip Somodevilla/Getty Images Mattis warns Syria not to use chemical weapons again

The Syrian regime should think carefully before using chemical weapons again, Defense Secretary Jim Mattis warned Friday, in an apparent reference to last year’s U.S. military strike on a regime airfield in retaliation for a previous chemical attack.

“You’ve all seen how we reacted to that,” Mattis said, adding that the Syrian regime “would be ill-advised” to launch more chemical attacks, as some recent reports from inside the country suggest.


Mattis acknowledged those reports and said the Pentagon was looking for evidence to confirm them. “Groups on the ground, NGOs, fighters have said" that the regime has used sarin gas in recent attacks, he said, but “we do not have evidence.”

The regime appears to have weaponized chlorine again, Mattis said, but “we are even more concerned about the possibility of sarin use.”

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“We think that they didn’t carry out what they said they’d do” in terms of destroying chemical weapons stores and production capabilities, Mattis added, confirming remarks earlier this week by State Department officials.

Mattis called Turkey’s offensive against Syrian Kurdish militants in Afrin “a distraction” from the fight against ISIS in Syria. “Welcome to the real world,” he said of balancing the interests of Turkey and the related Syrian Kurdish group that has been key to U.S. operations against ISIS.

Turkey has “legitimate security interests” in fighting the Kurdish PKK terrorist group, Mattis said, but the Kurdish-dominated Syrian Democratic Forces is the “one group that’s proven capable” of helping fight ISIS in Syria.