ANKARA: Turkey has detained a nephew of US-based Muslim cleric Fethullah Gulen’s after last week’s attempted coup, state-run media reported on Saturday, the first time one of his relatives has been apprehended in the current crackdown.

Muhammet Sait Gulen was taken into custody in Erzurum, eastern Turkey, and will be taken to the capital Ankara, the report said. His uncle in Pennyslvania is accused of “masterminding” the failed putsch through his movement.

After crushing the coup, Erdogan's government has demanded that the US hands over Gulen.

Gulen, 75, denies any involvement in the coup attempt. The United States has said Turkey, a NATO ally, needs to provide clear evidence of Gulen’s involvement in the coup before it can extradite him. Lawyers say the process could take many years.

On Saturday, Turkish Foreign Minister Mevlut Cavusoglu said the government expects to complete within a week to 10 days a dossier requesting the extradition of Gulen.

Cavusoglu told private broadcaster NTV in an interview the link between soldiers involved in the July 15 abortive coup and Gulen’s extensive network of followers was “very clear,” adding that Turkey would do all it could “politically and legally” to secure the extradition of the reclusive cleric.