Victor Kotsev and John Dyer

Special for USA TODAY

ISTANBUL — In the wake of the weekend coup attempt against President Recep Tayyip Erdogan, Turks increasingly point to a culprit outside their country's borders: the United States.

“It’s all America’s fault,” said Erkan Gul, 22, a sandwich shop worker. His evidence is the U.S. haven granted to Turkish Muslim cleric Fethullah Gulen, whom Erdogan blames for orchestrating the failed military coup.

The cleric's followers in Turkey "used to do some good things for the people. But then America corrupted Gulen, and now he is trying to take over Turkey,” the sandwich maker said.

Erdogan demands that the United States extradite Gulen, who has lived in Pennsylvania since 1999, but the U.S. insists Turkey first provide evidence of Gulen's complicity in the takeover attempt. That has created renewed tensions between the two NATO allies.

On Monday, allegations by government officials and media about U.S. involvement in the coup became so rampant that the U.S. ambassador to Turkey, John Bass, issued a statement denying any truth to the speculation.

“Some news reports — and, unfortunately, some public figures — have speculated that the United States in some way supported the coup attempt,” Bass said in his statement. “This is categorically untrue, and such speculation is harmful to the decades-long friendship between two great nations.”

In Washington, White House press secretary Josh Earnest echoed those comments. He said the United States would follow procedures in a decades-old extradition treaty and called Turkey's allegations that the U.S. was harboring Gulen “factually incorrect.”

Gulen, 77, who is in self-exile, used to be a close ally of Erdogan, but they had a falling out. He is now at the helm of a broad religious network that includes hundreds of schools across the world that promote a moderate version of Islam.

Alleged mastermind of attempted coup in Turkey is cleric living in Pennsylvania

Turkish Labor Minister Süleyman Soylu, a close Erdogan associate, blamed the United States during an interview Saturday with TV channel Haberturk.

“America is behind the coup,” Soylu said, according to an English translation in the Hurriyet Daily News, a respected Turkish newspaper. The minister cited “magazines” as describing the U.S. connection to the coup but declined to specify which ones.

Secretary of State John Kerry denied the accusations on Saturday.

Soylu might have been referring to a Newsweek opinion piece in March by Michael Rubin, a former Pentagon analyst who is now a scholar at the conservative American Enterprise Institute.

In the piece, Rubin speculated that Turkey’s army could pull off a coup with little opposition from the United States and other NATO allies. The article attracted attention and criticism from the Turkish government, but in recent days many Turks cited it as proof of Washington’s involvement.

Mehmet Demir, 43, a waiter at another restaurant near the Bosphorus, the waterway that divides this ancient city, said Turkey’s alliance with the United States was doing his country more harm than good.

“America is messing with the entire world,” Demir said. “The coup is all because of (Gulen's followers) and America.”

Dyer reported from New York.