Washington – US-based preacher Fethullah Gulen urged Washington on Tuesday to reject Turkey's efforts to extradite him and rejected as "ridiculous" the claim he was behind the past week's coup attempt."Turkish President Recep Tayyip Erdogan today once again demonstrated he will go to any length necessary to solidify his power and persecute his critics," Gulen said in a statement."I urge the US government to reject any effort to abuse the extradition process to carry out political vendettas."Gulen, who has lived in self-imposed exile in the United States since 1999, denies any involvement in the putsch."It is ridiculous, irresponsible and false to suggest I had anything to do with the horrific failed coup," he reiterated in the statement.Gulen is the spiritual leader of the Hizmet movement, which promotes moderate Islam across dozens of countries and is dubbed a terrorist group by the Turkish government.Turkey's Prime Minister Binali Yildirim said on Tuesday that his government had sent four files to the United States in a bid to secure the extradition of a man Ankara brands a "traitor."The White House said President Barack Obama discussed the extradition request during a phone call with Erdogan on Tuesday, during which he pledged US assistance in investigating the coup attempt.White House spokesperson Josh Earnest said the documents were being reviewed in light of the three-decade old extradition treaty that exists between the United States and Turkey.He also stressed that the cleric is entitled to certain rights by law.Last week's coup bid was the most serious threat to Erdogan since he took power first as prime minister in 2003, and saw rebel troops close down bridges in Istanbul, parliament bombed from the sky and protesters shot in the streets.It has raised deep concerns about the stability of the strategic NATO partner, which has a key air base used in the US-led fight against the Islamic State group that has a large nuclear weapons stockpile.Turkey has launched a massive post-coup purge, detaining thousands of people.The crackdown on military, police and the judiciary has widened to include schools and the media, and Turkish authorities Tuesday scrapped all TV and radio station licenses linked to what they call the "Fethullah Terrorist Organization," the government's derogatory name for the Gulen movement.