A Turkish court ruled on Dec. 11 to keep a U.S. consulate employee in jail as his trial on espionage charges continues, a lawyer said, meaning he will remain in detention until the next hearing in March.

The trial of Metin Topuz has been one many sources of strain between NATO allies Turkey and the United States, who have also been at odds over developments in Syria and Turkey’s purchase of Russian missile defense systems.

Topuz, a Turkish translator and fixer for the Drug Enforcement Administration (DEA) at the U.S. consulate in Istanbul, has been in custody for more than two years. The next hearing was set for March 10, said his lawyer, Halit Akalp.

Topuz is charged with espionage and links to the network of U.S.-based Islamic preacher Fethullah Gülen, widely believed to have orchestrated the July 15, 2016 failed coup attempt that left over 250 people dead.

Topuz denies the charges.

“The accusations made against me are just claims… There is no evidence that could even justify suspicion that I committed these crimes,” Topuz said during the hearing.

The court has repeatedly said it wants to hear one remaining witness in the case.