Turkey's state-run news agency says a court in Istanbul has ruled for a Turkish employee of the U.S. Consulate to remain in custody pending the outcome of his trial on charges of espionage and attempting to overthrow the Turkish government.

The court's interim decision Thursday, reported by the Anadolu Agency, was expected to further strain ties between the two NATO allies. Metin Topuz, who has been held in pre-trial detention for more than a year, was expected to be released.

Topuz, a translator and assistant for the U.S. Drug Enforcement Agency, is accused of links to U.S.-based Turkish cleric Fethullah Gulen, who the Turkish government blames for the 2016 coup attempt. Gulen denies any links to the failed coup.

Topuz, a 59-year-old Turkish citizen, denies the accusation. He faces a life sentence if convicted.