The detention of the Islamic State fighters is just one issue the United States is grappling with in its partnership with Syrian Kurds. American troops have fought alongside Kurdish-led militias on battlegrounds against the Islamic State in northeast Syria, and the Pentagon is showing no sign of backing away from them. At the same time, however, Washington is trying to tamp down escalating tensions in Syria between the Kurdish militias and Turkey, a longtime NATO ally that views the Kurds as a terrorist threat.

United States Special Operations troops advising the Kurdish-led militia known as the Syrian Democratic Forces are cataloging fingerprints and other so-called biometrics of many of the estimated 200 to 300 detainees in at least three camps near Raqqa. The American forces also are interrogating the detainees to learn more about foreign fighter networks and threats to their home countries.

But American military officials see parallels with the Iraq war, in which militants, including Abu Bakr al-Baghdadi, the current leader of the Islamic State, were held for years at Camp Bucca, a sprawling American detention facility on the Kuwaiti border where they became more radicalized.

“Clearly, we’ve seen what happens when you have a group of highly trained, terrorist fighters held in detention for a long time,” Col. Ryan Dillon, a spokesman for the American-led military coalition in Baghdad, said in a telephone interview. “We don’t want to see that, and it’s something we’re addressing.”

If so, the initial efforts appear tentative.

The Trump administration has quietly established an interagency working group, including officials from the State, Defense and Justice Departments, to help the Syrian Kurds deal with the problem. But American officials seem to want to wash their hands of the growing problem, despite the potential security and humanitarian risks.