Turkish media has reported that authorities found military "field sketches" in a USB drive in the possession of two Greek soldiers detained on March 2. Lt. Aggelos Mitredotis and Sgt. Dimitros Kouklatzis were charged with attempted military espionage when they were intercepted on the Turkish side of the Greek-Turkish border.

The soldiers, currently held in a prison in the city of Edirne on the border, have claimed they got "lost" while following "suspicious footsteps on the snow" in the border area and crossed to the Turkish side by mistake.

Investigators are still analyzing the contents of the USB drive as well as two personal cellphones and a military-issue encrypted phone the two men had in their possession. A hearing is not scheduled yet for the soldiers, who have added further strain to deteriorating Turkish-Greek ties.

The suspects also shot a video of the Turkish border, but have claimed they were simply recording it to show the area they were "patrolling" to their superiors. Athens has backed their claim and Greek authorities have said that the men "accidentally strayed" over the Turkish side because of adverse weather.

The Greek-Turkish border is tightly monitored by both parties due to the massive refugee influx into Europe since 2015, and because of terror threats.

The two countries had improved their ties after a presidential visit to Athens last year but hostilities re-emerged recently. Greece was accused of provocation by Turkey when its ships violated Turkey's "territorial waters" in the Aegean Sea. Ankara has also been critical of Athens after Greek courts rejected the extradition of putschist soldiers involved in the 2016 coup bid in Turkey.