Assad agreed to turn over his chemical weapons stockpile earlier this month in order to prevent U.S. military strikes against the dictator. But McCain questioned Assad’s sincerity, citing news reports that the Syrian military is starving cities where rebels have the upper hand.

“They have 12,000 people encircled that they’ve already gassed … so now they’re going to ‘let them starve for a bit,’” McCain said. “These are the same people — apparently government forces — who are ‘cooperating’ with us on chemical weapons.”

McCain said that the chemical weapons agreement is doing nothing to address the civil war in Syria. McCain has frequently called on the United State to get more involved in order to help rebels fighting Assad.