Turkey is preparing an extradition request for US-based cleric Fethullah Gulen, whom Turkey blames for a failed coup. Gulen has said he would obey any extradition ruling from the US but said that President Tayyip Erdogan had staged the putsch. Turkey's justice and foreign ministries will write to Western governments to demand the return of Gulen's supporters from those countries. Gulen, who is living in self-imposed exile in Pennsylvania, denied any involvement in the coup. US Secretary of State John Kerry said the US had not yet received a formal request from Turkey for Gulen's extradition. Meanwhile, Turkey has widened its crackdown on suspected supporters of a failed military coup, arresting Gen. Bekir Ercan Van, commander of the Incirlik Air Base, and an "order of detention" for Col. Ali Yazici, a senior military aide to Erdogan.