The Trump administration on Thursday thanked Turkey for its reduced sentence for an imprisoned U.S. scientist but continued to demand his immediate release.
The State Department said there was no "credible evidence" in Turkey's case against NASA scientist Serkan Golge.
Turkey sentenced Golge to 7½ years in prison in February on charges of belonging to an outlawed group that Turkey blames for attempting a coup that failed in 2016. The verdict was appealed. A court in Adana threw out the conviction, ruled instead that Golge had aided the group, and reduced the sentence to five years.
Golge's lawyers said they would appeal his case again to a higher court.
Golge is a research scientist with the U.S. space agency. He and his family were visiting his native Turkey in 2016 when the coup attempt was carried out.
He was swept up in the mass arrests of tens of thousands of people suspected of playing a part in trying to overthrow the Turkish government.
Golge insists he is innocent. His wife says that he was arrested because he is an American citizen and that Turkey is holding him hostage.
The Golge case and that of another jailed U.S. citizen accused of participating in the failed coup, clergyman Andrew Brunson, have caused tension between the United States and Turkey.