ISTANBUL (Reuters) - A Turkish-U.S. citizen and former NASA scientist jailed in Turkey on terrorism charges plans to file an appeal to Turkey’s top court after a lower appeals court reduced his sentence this week, his lawyer said on Friday.

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Serkan Golge was visiting family in southern Turkey when he was arrested in a crackdown following a failed military coup in 2016 which the government blames on supporters of U.S.-based Muslim cleric Fethullah Gulen.

Golge’s case is similar to that of American pastor Andrew Brunson, whose ongoing detention in Turkey in connection with the coup attempt is the cause of a major row between NATO allies Washington and Ankara, and has led to U.S. President Donald Trump imposing sanctions on Turkey.

In a ruling on Wednesday, Turkey’s Court of Appeals changed Golge’s conviction charge to aiding, rather than being a member of, a terror organization, and to reduce his 7-1/2-year prison sentence to five years. Golge denied both charges.

“We have already filed an appeal for his release to a higher court and we will go to the Yargitay (appeals court) afterwards,” Ali Bilgin, a lawyer representing Golge in Turkey, told Reuters.

Washington welcomed Wednesday’s ruling and said it would follow the case closely along with those of other citizens and local U.S. mission employees.

“We welcome the Turkish Court of Appeals’ decision to reduce the sentence against Dr. Golge,” U.S. state Department spokeswoman Heather Nauert said on Thursday. She also called for Golge’s release in a case that lacks “credible evidence”.

Golge was visiting family in southern Turkey when he was arrested. Turkey has detained 160,000 people and dismissed nearly the same number of civil servants over suspected links to the coup attempt, the U.N. human rights office said in March. Of those detained, 77,000 have been formally charged and kept in jail during trial, the interior minister said in April.

Cleric Gulen denies involvement in the attempted putsch in which 250 people were killed.

Along with sanctions, Trump has imposed double traded tariffs on Turkey, exacerbating a slide in the lira.