The stakes of the U.S. retreat in Syria

CBS News foreign correspondent Holly Williams, who spent years covering the civil war in Syria, reports on the American drawdown and an alliance with the Kurds left behind

The stakes of the U.S. retreat in Syria

CBS News Foreign correspondent Holly Williams, who has reported on the Syrian civil war for years, tells 60 Minutes Overtime that Turkey's new offensive against Kurds in the region could potentially be very good news for ISIS.

"The group on the ground that has been doing all the fighting against ISIS is this Kurdish-dominated group, the Syrian Democratic Forces, or SDF, America's closest partners… in the fight against ISIS," Williams said. "They are the targets of this Turkish incursion. And now they're busy fighting against Turkish forces, instead of continuing to fight against ISIS."

Williams and a 60 Minutes crew were in the region in June 2018, when the so-called Islamic State caliphate was crumbling, and reported on the relationship the SDF had forged with the U.S. military.

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"They had the protection of the U.S. from the air and the help of the U.S. on the ground," Williams said. "And in return, the SDF did the bulk of the fighting against ISIS."

The Kurds were guarding several prisons containing former ISIS fighters and their families. In September of this year, Williams was shown security camera footage of an attempted escape of one of those prisons by ISIS fighters.

"And they stopped it," Williams said. "But the fear is, that it's much easier to do that when the SDF don't have the resources to properly guard those prisons."

"The Turks are saying that part of their mission in going into Syria is that they'll look after those ISIS prisoners," Williams said. "The problem is it's highly unlikely, given that the Turkish are fighting against the SDF, that they're gonna walk up to the prison and there's gonna be a friendly handover of these… ISIS prisoners."

Williams said the chaos caused by the Turkish incursion increases the chances of a mass prison break.

"Then it's about, once again, back to square one, rounding up these thousands of ISIS fighters," Williams said.

The story above was produced by Keith Sharman and Omar Abdulkader. It was edited by Will Croxton and Aisha Crespo.