Turkey's president Tayyip Erdogan has said the official process with the US for Fethullah Gulen's extradition has started. The announcement came during an interview with Al Jazeera in Ankara. Erdogan said he believed the US-based cleric was behind last week's attempted military coup. Gulen has repeatedly denied plotting the the incident.

His spokesman Alp Aslandogan said that neither Gulen nor his lawyers have been contacted by U.S. authorities regarding the extradition request. The US Department of Justice has not confirmed that an official extradition request has been filed.

"As long as the extradition request is filed properly, legally and the proper procedure is followed. We're not worried at all, Mr. Edrogan expressed the extradition demand publicly actually two years ago and they have been talking about it but so far they have not filed an official request. Now, there is news that they have filed. Something about it was not recognized as an official request yet. Maybe it will be recognized as such as long as the proper procedure is followed we are not worried," Spokesman and adviser for Fethullah Gulen Alp Aslandogan said.