"The soldiers are in the process of being returned to Turkey. It will probably happen today," the source told AFP, declining to comment further.

The incident near the border town of Feres comes just weeks after the release of two Greek soldiers held in Turkey since March after a similar incident.

The Greek soldiers told Turkish prosecutors shortly after their arrest that they had mistakenly crossed the border after getting lost in the fog.

The prosecution said the pair testified they entered the Turkish side by tracking footsteps in the snow and filmed images on their mobile phones to send to higher ranking officials.

The case strained relations between the neighbours and NATO allies, with Turkey demanding that Greece hand over eight Turkish troops wanted over the July 2016 attempted coup aimed at unseating President Recep Tayyip Erdogan.