Authorities in western Turkey have arrested the brother of cleric Fethullah Gulen, who lives in self-imposed exile in the United States and is blamed by Ankara for a coup attempt, news agency DHA reported on Tuesday.
Turkish prosecutors in the western city Izmir accused Kutbettin Gulen of being part of a terrorist organization. Izmir police had previously arrested him in early October.
Within days of the Turkish military's failed coup attempt in July, Ankara declared a state of emergency and launched a massive purge of the army and civil service to remove suspected supporters of Fethullah Gulen, Erdogan's one-time ally who now tops Ankara's most-wanted list.
Turkish authorities have also formally requested the extradition of the 78-year-old cleric from the United States.
During questioning, Gulen's brother rejected all charges against him and said there was no such "organization," according to DHA.