Prosecutors in the western city of Izmir, where Andrew Craig Brunson served as a pastor, have demanded up to 35 years of prison for espionage charges and his links to the Gülenist Terror Group (FETÖ) and the PKK.

In an indictment prosecutors presented to the court, Brunson is accused of committing crimes on behalf of the FETÖ and PKK terrorist group, and obtaining classified state information for political and military purposes, facing up to 15 and 20 years in jail, respectively.

A hearing will be set for Brunson if the court accepts the indictment.

The case of Brunson, who was a pastor at the Diriliş (Resurrection) Protestant church in Izmir, is a thorny issue between Ankara and Washington. Washington has repeatedly called for the release of Brunson, claiming he was "unjustly detained."

Departing U.S. Secretary of State Rex Tillerson was the last high-ranking U.S. official to demand his release during a visit to Turkey last month, disregarding judiciary independence. The Turkish government has repeatedly told Washington that Brunson's case is being handled by the courts and the government can't intervene.

FETÖ, led by Pennsylvania resident Fetullah Gülen, is implicated in a string of criminal inquiries, the most significant of which is trials related to the deadly coup attempt of July 15, 2016 through its infiltrators in the military that killed 249 people.

The U.S. did not respond positively to Turkey's requests to extradite or arrest Gülen to prevent his escape to another country.

Brunson was arrested after a secret witness in a criminal probe into the FETÖ testified against him while authorities were preparing to deport Brunson and his wife Norine Lyn for "involvement in actions threatening national security."

The indictment underlined the pastor's links to the terrorist group and his frequent contacts with Bekir Baz, a fugitive point man for the FETÖ in the Aegean region where Izmir is located, his aide Murat Safa, and Amnesty Turkey Branch Executive Taner Kılıç, who is also being accused of aiding the FETÖ.

The charges were first voiced by a secret witness, playing a key part in the launch of the investigation. The pastor and his wife – who was released earlier – were members of FETÖ which funded their church, the witness had said.

Even before he was questioned by prosecutors about his links to the FETÖ, Brunson was accused of espionage and attempting to overthrow the constitutional order (a coup charge). Brunson had denied those initial allegations, but the indictment accused Brunson with making speeches praising the FETÖ and the PKK at the church.

The indictment also charged Brunson with conducting systematic efforts targeting Kurdish citizens and founding the "Kurdish Church of the Messiah," where only Kurds are admitted. There is also evidence showing Brunson with PKK flags and symbols, it said, adding that Brunson frequently visited Ayn al-Arab, also known as Kobani, in northern Syria, which is being controlled by the PKK's Syrian offshoot the Democratic Union Party (PYD) and its armed wing the People's Protection Units (YPG), and Turkey's Suruç district in southeastern Şanlıurfa province across the border.

Brunson also took part in organizing the 2013 Gezi Park riots, the indictment noted, claiming that he was in possession of lists containing the names of "gas station workers in Turkey's southeast," "railway employees," or "soldiers to get in contact with," whom with he exchanged information through close contacts.

The indictment also noted that the suspect was charged with being in contact with retired soldiers, special warfare officers or high-rank executives of the PKK and FETÖ, which is understood through two secret and five open witness statements, along with evidence as digital data, documents, phone conversation and wireless tower records provided by Brunson himself, witnesses and authorities.

The FETÖ, which posed as a charity with religious undertones for decades before using its immense clout to seize power through infiltrators in the military, is known for its close ties with churches.

Under its "interfaith project", Gülenists reached out to Protestant and Catholic churches, though it is the first time that a pastor is being implicated in a FETÖ case.

The terrorist group's ties to the United States and its intelligence service are no secret, according to prosecutors in other cases against the FETÖ.

While media reports claim that it is not confirmed if Brunson is "a U.S. agent" or not, a separate indictment by prosecutors in Ankara says FETÖ used its sprawling international network of schools to provide a cover for CIA operatives.

The FETÖ's coup attempt in 2016 was quelled thanks to a strong public resistance. Thousands of people, from military officers who opened fire on unarmed crowds rallying against the coup to "civilian" point men of the terrorist group, were arrested or detained under a state of emergency.

Trials of hundreds involved in the putsch attempt are still underway. In 104 trials since 2016, 797 defendants involved in the insurrection bid were handed down life sentences.

Some 586 defendants, including generals, were sentenced to life. A main trial of those accused of orchestrating the coup plot and a trial of putschists who took over the main headquarters of the army, are still underway.

Bekir Baz, one of the group's point men who had ties to Brunson, is believed to be in the U.S. after he fled Turkey in 2015 one year before the coup attempt. He managed to run away at a time of heightened crackdowns against the terrorist group.

Baz was allegedly a coordinator of the group's activities in Izmir where Gülen made himself a name as a charismatic preacher in the 1970s. He reportedly blackmailed and threatened local officials to work for the group's interests, according to criminal investigations.