DIYARBAKIR, Turkey — Mosul and its surroundings, which have been under Islamic State (IS) occupation for two years, are quite active these days. Kurdish forces besieging Mosul alongside the Iraqi army are frequently targeted in multipronged assaults by IS.

Telskuf — northwest of Mosul and a base for Kurds as well as American military specialists supplying coordinates to coalition aircraft — has been a target in IS' sight. An American was wounded in an assault there launched May 4. As is often the case, a medevac helicopter couldn’t extract the wounded American because of heavy fire in the area. Instead, a group of Kurdish fighters carried the American to safety in a building, where they quickly came under IS fire from a nearby ambush position.

It took hours of sustained exchanges of fire to push the IS fighters back. Eight Kurdish fighters in the building were wounded, but they kept the American safe until a helicopter arrived. During the clashes, a middle-aged man attracted attention by issuing instructions to Kurdish fighters. From his accent, it was clear that he wasn’t an Iraqi Kurd, but the directives he gave showed that he knew about fighting.

That man was Sait Curukkaya, 48, who was born in Bingol, Turkey. The Kurds know him as Dr. Suleyman. Curukkaya, a former member of the Kurdistan Workers Party (PKK), has been in action against IS for months while also training volunteers to fight the militant group. His combat experience derives from his time with the PKK.