Authorities have detained four suspected senior ISIS extremists, including a close associate of the group’s leader Abu Bakr al-Baghdadi, in an operation in the Aegean coastal city of Izmir, Turkish media reported on Friday. The suspects include the groups so-called "emir," or ruler, of Deir Ezzor, a major city in eastern Syria, and its environs. He is identified only by the initials K.E.H., Hurriyet newspaper said. Turkeys state-run news agency Anadolu described the other three suspects as senior operatives within the extremist group. Hurriyet said the four were captured as part of a joint operation by Turkeys intelligence agency and police anti-terrorism units. The suspects were hiding among a group of Syrian refugees planning to cross into Europe, the newspaper reported. The four are being questioned by anti-terrorism police in Izmir. Police in the city confirmed the operation but could not immediately provide details.