U.S. scientist Serkan Gölge released from Turkish prison - journalist

A Turkish-American scientist held in Turkey since July 2016 on terror charges has been released, journalist Tuğba Tekerek said in a series of tweets on Wednesday.

Serkan Gölge was released from İskenderun Prison on Wednesday evening, Tekerek said, citing information received from Gölge’s family.

U.S. State Department spokesperson Morgan Ortagus confirmed the release at a filmed press briefing on Wednesday evening.

The former NASA scientist was arrested on July 23, 2016, shortly after Turkey’s Justice and Development Party (AKP) fended off an attempted coup by factions in the Turkish military.

Gölge received a seven-and-a-half-year prison sentence in February 2018 for membership of the Gülen religious movement, which the AKP blames for orchestrating the coup attempt.

Prosecutors said Gölge held an account at a bank linked to the Gülen movement and had attended one of its universities. They also presented his possession of a $1 bill, said to be a mark of membership of the movement, as evidence in Gölge’s trial.

The scientist denies membership of the movement, and told Tekerek in 2018 he believed the Turkish government had ordered his detention to use as leverage in its relations with the United States.

Gölge is one of several U.S. citizens and employees who have been arrested since the coup attempt. The highest profile detainee, American pastor Andrew Brunson, was released last October after months of pressure from the U.S. government, including sanctions which contributed to a large lira slide last year.

Tekerek reported that Gölge’s case file had been with the Court of Cassation for review for a long period, adding that the scientist’s lawyers had said he may have been released for time already served.

The initial sentence was reduced to five years by a court last September, at which point Gölge had already served around two years in prison.

The scientist's release is good news for U.S. lawmakers, who introduced a bill in April calling for measures to be taken against Turkey for the detentions of Gölge and jailed employees of U.S. consulates in Turkey.

However, it alone is unlikely to spell the end of the countries’ disagreements. Turkey is on the verge of buying Russian S-400 missile defence systems, a move that will draw measures including likely sanctions from the United States.

There were signs of a shift on that front, after the countries' leaders reportedly discussed the deal on Wednesday, shortly before Gölge's release.

Fahrettin Altun, the communications director for the Turkish presidency, said President Recep Tayyip Erdoğan and his U.S. counterpart Donald Trump had discussed a "working group" on the S-400 purchase during a phone conversation on Wednesday.

Ortagus declined to comment on whether Gölge's release was linked to the S-400 issue, but commended the Turkish authorities for releasing the scientist.