WASHINGTON (Reuters) - U.S. authorities should search through any intercepted communications of Fethullah Gulen to seek evidence backing Turkey’s accusation that the U.S.-based Muslim cleric orchestrated last year’s failed coup, Turkey’s envoy to Washington said on Friday.

U.S.-based Turkish cleric Fethullah Gulen at his home in Saylorsburg, Pennsylvania, U.S. July 10, 2017. REUTERS/Charles Mostoller

In an interview with Reuters almost a year after the coup attempt, Ambassador Serdar Kilic expressed frustration over the halting U.S. response to its request for Gulen’s extradition and urged Washington to use its data-collection capabilities to help prove Ankara’s accusations against him.

“They should help us in this regard. We don’t have national intelligence authority in the United States,” he said at the Turkish embassy.

President Donald Trump’s administration is taking Turkey’s extradition request “more seriously” than Trump’s predecessor, Barack Obama, Kilic told a news conference later on Friday, but he did not elaborate.

Kilic said the United States had not given any sign of when it would decide what to do with Gulen, who denies any involvement in the July 15, 2016, coup attempt.

Kilic cited confessions by some alleged coup plotters and visits he said they paid Gulen at his Pennsylvania compound in the days leading up to the failed putsch as proof that the 79-year-old cleric was behind the coup, in which more than 240 people were killed.

However, Kilic acknowledged in the Reuters interview that more concrete evidence of direct involvement by Gulen, who has lived in self-imposed exile since 1999, remains elusive.

“If you are asking for a written instruction by Fethullah Gulen to the members of the Fethullah Gulen Terrorist Organization in the army, that would be a futile request,” Kilic said, adding that the planning was done in secrecy.

Alp Aslandogan, Gulen’s media adviser, said the cleric does not own a cellphone, the land line at his compound is attended by staff members and he does not use email, suggesting that any effort to scour Gulen’s communications might yield little.

He also said he had not seen any signs of the Trump administration giving the Gulen extradition case a higher priority.

He said confessions of coup plotters implicating Gulen were suspect because of accusations that their testimony was “obtained under duress and sometimes torture.”

Ankara has repeatedly denied the accusations while saying a firm security posture is needed in the face of dangers it also faces from Kurdish militants as well as wars in neighboring Iraq and Syria.

The U.S. Justice Department declined any comment on the case.

STALLED EXTRADITION

President Tayyip Erdogan said in May he would pursue “to the end” Gulen’s extradition and has waged a post-coup crackdown on his followers.

Kilic told reporters on Friday that U.S. officials had requested further evidence, in addition to 84 boxes of documents already provided, and that Turkey was working to comply.

He said in the meantime Turkey wants the United States to limit Gulen’s freedom of movement.

Aslandogan said the call for such restrictions on Gulen, who is frail-looking and walks with a shuffle, was part of a “harassment campaign” by the Turkish government.

Prospects for the U.S. extradition of Gulen appeared to dim in February when Trump’s former national security adviser Michael Flynn resigned over his failure to disclose the extent of his contacts with Russia.

Kilic said he met Flynn, who was outspoken in favor of Gulen’s extradition, “a couple of times,” described him as “visionary” and said he wished Flynn were still in office.