(FILES) This handout file picture released on September 24, 2013 by Zaman Daily shows exiled Turkish Muslim preacher Fethullah Gulen at his residence in Saylorsburg, Pennsylvania.  
The US-based cleric was accused by Ankara of orchestrating Friday's military coup attempt but he firmly denied involvement, also condemning the action "in the strongest terms". / AFP PHOTO / ZAMAN DAILY / SELAHATTIN SEVI / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO/ZAMAN DAILY/SELAHATTIN SEVI" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE

SELAHATTIN SEVI/AFP/Getty Images
SELAHATTIN SEVI/AFP/AFP/Getty Images
(FILES) This handout file picture released on September 24, 2013 by Zaman Daily shows exiled Turkish Muslim preacher Fethullah Gulen at his residence in Saylorsburg, Pennsylvania. The US-based cleric was accused by Ankara of orchestrating Friday's military coup attempt but he firmly denied involvement, also condemning the action "in the strongest terms". / AFP PHOTO / ZAMAN DAILY / SELAHATTIN SEVI / RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO/ZAMAN DAILY/SELAHATTIN SEVI" - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE SELAHATTIN SEVI/AFP/Getty Images
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Story highlights

The demand could foment a crisis in U.S.-Turkey relations

A similar episode took place in 1979 when the U.S. refused to extradite the Shah of Iran

(CNN) —  

Less than 24 hours after surviving a military coup, Turkey’s embattled President Recep Tayyip Erdogan has demanded the U.S. hand over the man he says was responsible for Friday’s putsch.

The demand could foment a crisis in U.S.-Turkey relations, since the U.S. is unlikely to want to honor the request without hard evidence, which could affect Turkey’s role as a key ally in the fight against ISIS and the handling of refugees fleeing the Syrian civil war.

Erdogan issued the call while addressing a crowd of supporters in Istanbul Saturday.

“I call on the United States and President Barack Obama: Dear Mr. President, I told you this before, either arrest Fethullah Gulen or return him to Turkey. You didn’t listen,” Erdogan told his backers.

Gulen, a former ally and cleric, now resides in exile in Pennsylvania. Erdogan blamed him almost immediately on Friday.

Who is Fethullah Gulen?

Secretary of State John Kerry told CNN’s Jake Tapper Sunday that Turkey has made no formal request for extradition – and that he’d asked the country’s foreign minister to make the official request, saying that “the United States is not harboring anybody.”

“We have always said, ‘Give us the evidence, show us the evidence, we need a solid, legal foundation that meets the standards of extradition in order for our courts to approve such request,’ ” he told Tapper on “State of the Union.”

“So we’re waiting for that,” Kerry said. “They tell us they are putting it together and will send it to us. But we think it’s irresponsible to have accusations of American involvement when we’re waiting on their request.”

State Department spokesman John Kirby said late Saturday that Kerry had spoken with the Turkish foreign minister and during that call Kerry had offered U.S. assistance with an investigation into those involved with the coup. But he added that “public insinuations or claims about any role by the United States in the failed coup attempt are utterly false and harmful to our bilateral relations.”

When asked about the possibility of Gulen’s extradition in June, Kirby told reporters that, “We don’t talk, as you know, about the specifics of extradition cases one way or the other.”

The cleric has lived in the U.S. since 1999 and has never been charged with a crime during that time.

On Saturday, however, Erdogan further implored the U.S. in Istanbul: “I call on you again, after there was a coup attempt, extradite this man in Pennsylvania to Turkey! If we are strategic partners or model partners, do what is necessary.”

Gulen, 75, denied the allegations in a statement Friday night, saying, “As someone who suffered under multiple military coups during the past five decades, it is especially insulting to be accused of having any link to such an attempt. I categorically deny such accusations.”

In an interview on Saturday with Reuters, Gulen said he didn’t know who was behind the coup: “I have been away from Turkey for 16 years. I have not been following these developments, therefore I cannot say anything about that.”

Gulen also cast doubt on the prospect of his being extradited. “They have voiced such requests without making formal requests in the past,” Gulen said prior to Erdogan’s speech.

The situation risks developing into a major crisis in U.S.-Turkey