The Kurdish Regional Security Council announced in a statement on Friday that it captured a senior Islamic State figure, Socrates Khalil.
Khalil was known to be a confidant of the late Islamic State leader, Abu Bakr al-Baghdadi.
"After spending five years in Turkey, Khalil returned to Kurdistan with a forged passport and was swiftly apprehended," the statement said.
Khalil made bombs for the Islamic State and was entrusted by al-Baghdadi with various major operations, the statement added, saying that he was instrumental in the 2014 Islamic State takeover of Mosul, and participated in many battles against Iraqi forces and the Peshmerga forces.