An American citizen who joined the Islamic State in Syria has been captured by advancing U.S.-led coalition forces, according to a new report.

The American jihadist was reportedly captured by Syrian Kurds, who have been one of the most effective local fighting forces working to destroy the self-proclaimed caliphate. The Kurds, who have formed an umbrella unit called the Syrian Democratic Forces that includes some Arab partners, then handed him over to U.S. officials.