By Roberta Rampton and Lesley Wroughton
WASHINGTON (Reuters) - President Barack Obama and Turkish President Tayyip Erdogan discussed the status of U.S.-based cleric Fethullah Gulen, blamed by Turkish authorities for masterminding a recent failed coup, during a call on Tuesday, the White House said.
The Turkish government has filed material in electronic form about Gulen with the U.S. government, which has been waiting for a formal extradition request, White House spokesman Josh Earnest said.
U.S. officials have said Turkey must provide proof that Gulen was involved in the coup attempt. Any extradition request from Turkey, once submitted, would be evaluated under the terms of a treaty between the two countries, Earnest said.
Obama offered U.S. assistance for Ankara's investigation into the attempted coup and pressed Erdogan to proceed according to the democratic principles outlined in Turkey's constitution, Earnest said.
"The principles of democracy should be adhered to even as a thorough investigation is conducted," he said.
The U.S. State Department said it was still in the process of analyzing the documents submitted by Turkey and could not characterize them as an extradition request for Gulen.
Gulen, a 75-year-old former ally of Erdogan, has lived in self-imposed exile in Pennsylvania since the late 1990s. He has denied any involvement in the abortive coup.
Earlier, Turkey's Justice Ministry it had sent a dossier to the United States on Gulen, but did not make clear whether that amounted to an official extradition request.
A request to extradite Gulen would face legal and political hurdles in the United States.
Lawyers at the State and Justice departments would review it to determine if the alleged offense is a crime in both countries and whether it falls within the scope of the countries’ extradition treaty. The request would then go before a judge, who would rule on whether probable cause existed that a crime was committed and that the accused person did it.
If the request survived those tests and is found lawful, it would still need to get the approval of U.S. Secretary of State John Kerry, who can consider non-legal factors, such as humanitarian arguments.
The U.S.-Turkey extradition treaty went into force in 1981 and covers any offense punishable in both countries by more than a year in prison. It does not cover offenses “of a political character,” although it does cover “any offense committed or attempted against a head of state or a head of government,” according to the treaty.
Separately, the State Department said Deputy Secretary of State Tony Blinken met with the Turkish ambassador on Tuesday in Washington and likely discussed the extradition issue as well as broader issues.
(Additional reporting by Julia Harte, David Ingram, Doina Chicau and David Alexander; Editing by Tom Brown)