Salih Fidan and Samet Gure, who were handling the terror group's activities in Iraq, were arrested while trying to illegally cross the Ukraine-Poland border.
The so-called heads of the Fetullah Terrorist Organisation, also known as FETO, of two major cities in Iraq have been brought to Turkey from Ukraine, the Turkish Interior Ministry has announced.
In a statement on Wednesday, the ministry said that Salih Fidan and Samet Gure, who are the terror group's chiefs in Baghdad and Erbil, respectively, were arrested while trying to illegally traverse the Ukraine-Poland border.
A Turkish court had issued arrest warrants for both men over their suspected membership in FETO, the group behind the 2016 defeated coup, the statement added.
The suspects are currently in the capital Ankara, where they are being processed at the Chief Public Prosecutor's Office.
According to the statement, Fidan played a role in the organisation's overseas activities and was a teacher at a FETO-linked university in Iraq.
Fidan had departed from Turkey with his wife just after the July 15 coup attempt and had not returned since, it added.
Gure also actively served the terror organisation outside Turkey while working as a physics teacher at another education institution in Erbil, also linked to FETO.
According to the statement, Gure deposited more money into his account at the FETO-linked Bank Asya following an earlier coup attempt by the terror group in 2013, and was also named in the testimonies of former members of the group.
READ MORE: What is FETO?
December 17-25, 2013 saw a graft probe and the detention of prominent figures in a FETO plot to overthrow Turkey's elected government.
FETO and its US-based leader Fetullah Gulen also orchestrated the defeated coup of July 15, 2016, which left 251 people martyred and nearly 2,200 injured.
Ankara also accuses FETO of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.