Turkey will not compromise with Washington over the extradition of the cleric it accuses of standing behind an abortive coup, Prime Minister Binali Yildirim said on Saturday, warning of rising anti-Americanism if the U.S. fails to extradite.

Yildirim’s comments, at a briefing for local reporters, are the latest to take aim at Turkey’s NATO ally and coincided with a report that an Istanbul prosecutor wrote to U.S. authorities requesting the detention of the cleric, Fethullah Gulen.

“There is no compromise apart from this chief terrorist coming to Turkey and being prosecuted,” Yildirim was quoted as saying by state-run Anadolu Agency.

“The only way to prevent the rising (negative) sentiment against America is for the U.S. to hand over this man and make sure Turkey’s justice system holds him accountable.”

Turkey’s foreign minister said this week documents had been sent to the United States and that Turkey had received “positive signals” about Gulen’s possible extradition, but Turkey has not said clearly whether it has filed a formal extradition request.

The White House said on Saturday that U.S. Vice President Joe Biden will visit Turkey on Aug. 24, the first visit by a high-ranking U.S. official since the failed coup.

Yildirim said a U.S. technical team would visit Turkey on Aug. 22 to discuss legal issues relating to the possible extradition, according to Anadolu. He said Secretary of State John Kerry is due in October, broadcaster CNN Turk reported.

Yildirim said he believed there would be a “positive outcome” with the United States on the extradition, Anadolu said.

U.S. officials have said that the United States has a formal process for dealing with extradition requests and that Turkey must provide solid evidence of Gulen’s involvement.

The Istanbul chief prosecutor sent a letter to U.S. authorities asking for Gulen’s detention, CNN Turk said.

Turkey’s Justice Ministry passed on the letter, which accused Gulen of 10 charges including attempting to overthrow the government, to the United States, it said.

Gulen said on Friday he would only hand himself over to Turkish authorities if an independent international investigative body first found him guilty.

“If a tenth of the accusations against me are established, I pledge to return to Turkey and serve the heaviest sentence,” he said in an opinion piece in French daily Le Monde.

Turkey will not compromise with Washington over the extradition of the cleric it accuses of standing behind an abortive coup, Prime Minister Binali Yildirim said on Saturday, warning of rising anti-Americanism if the U.S. fails to extradite.

Yildirim’s comments, at a briefing for local reporters, are the latest to take aim at Turkey’s NATO ally and coincided with a report that an Istanbul prosecutor wrote to U.S. authorities requesting the detention of the cleric, Fethullah Gulen.

Turkey says Gulen, who has lived in self-imposed exile in rural Pennsylvania since 1999, masterminded the failed July 15 coup when a group of rogue soldiers commandeered tanks, warplanes and helicopters in an attempt to overthrow the government. Gulen has denied the charge and condemned the coup.

“There is no compromise apart from this chief terrorist coming to Turkey and being prosecuted,” Yildirim was quoted as saying by state-run Anadolu Agency.

“The only way to prevent the rising (negative) sentiment against America is for the U.S. to hand over this man and make sure Turkey’s justice system holds him accountable.”

Turkey’s foreign minister said this week documents had been sent to the United States and that Turkey had received “positive signals” about Gulen’s possible extradition, but Turkey has not said clearly whether it has filed a formal extradition request.

The White House said on Saturday that U.S. Vice President Joe Biden will visit Turkey on Aug. 24, the first visit by a high-ranking U.S. official since the failed coup.

Yildirim said a U.S. technical team would visit Turkey on Aug. 22 to discuss legal issues relating to the possible extradition, according to Anadolu. He said Secretary of State John Kerry is due in October, broadcaster CNN Turk reported.

Yildirim said he believed there would be a “positive outcome” with the United States on the extradition, Anadolu said.

U.S. officials have said that the United States has a formal process for dealing with extradition requests and that Turkey must provide solid evidence of Gulen’s involvement.

The Istanbul chief prosecutor sent a letter to U.S. authorities asking for Gulen’s detention, CNN Turk said.

Turkey’s Justice Ministry passed on the letter, which accused Gulen of 10 charges including attempting to overthrow the government, to the United States, it said.

Gulen said on Friday he would only hand himself over to Turkish authorities if an independent international investigative body first found him guilty.

“If a tenth of the accusations against me are established, I pledge to return to Turkey and serve the heaviest sentence,” he said in an opinion piece in French daily Le Monde.