Gulen wants international inquiry into failed coup in Turkey

US-based preacher Fethullah Gulen has called for an international inquiry into last month's failed coup in Turkey, vowing his "full cooperation" with any such probe of the putsch over which Ankara is seeking his extradition.

Writing in Saturday's edition of the French newspaper, Le Monde, Gulen strenuously rejected accusations by Turkey that he ordered the 15 July attempt to remove Recep Tayyip Erdogan from the presidency.

"I'm asking that an independent international commission investigate this attempted coup," the Pennsylvania-based preacher wrote, promising his "full cooperation".

"If a tenth of the accusations levelled at me are proven, I will return to Turkey to face the stiffest punishment," Gulen, 75, added.

A one-time ally of Erdogan turned arch-foe, Gulen has lived in self-imposed exile in the US since 1999.

He has dismissed the accusations against him and his Hizmet movement, which runs a network of private schools, businesses and media outlets, as a "witch hunt".

"Claiming I could, from 10,000km away, push the army to conduct a putsch against the government is slander," he wrote.

"However, if soldiers claiming to be supporters of Hizmet were involved in this plot, I say without hesitation they are felons, who have shaken the unity and integrity of the country."

But Gulen said the actions of some such supporters, who may have been "influenced by the army's penchant for intervention... cannot be blamed on all followers of the movement".

Gulen said he enjoyed warm ties with several former Turkish leaders, from liberal ex-president Turgut Ozal in the 1980s to his conservative successor Suleyman Demirel and Bulent Ecevit, the social-democratic prime minister from 1999 to 2002.

"I lent my support to all their policies," he wrote, adding that they in turn had shown him respect because of his movement's work in promoting education and social work.

Things were different with Erdogan, said Gulen.

"Although I have always had reservations about political Islam, I also supported Mr Erdogan and the AKP at the start, when big democratic reforms were launched."

But over the past three years, since a corruption scandal embroiling several of Erdogan's ministers erupted, he has been repeatedly accused of running a "parallel state".

Turkey's crackdown on Gulen's supporters has intensified since the July coup attempt.

Tens of thousands of people from the military, judiciary, civil service and education suspected of links with Gulen's movement have been dismissed from their jobs or arrested.