They claim it happened near the Evros river, which flows for more than 150km from Bulgaria to the Mediterranean Sea.
The Greek police have denied the allegations.
Al Jazeera's Laurence Lee reports from northern Greece.
Since March 2015, Saudi Arabia and a coalition of Arab states have launched more than 19,278 air raids across Yemen.
Many Pentecostal churches in the Niger Delta offer to deliver people from witchcraft and possession - albeit for a fee.
No, it wasn't because of WMDs, democracy or Iraqi oil. The real reason is much more sinister than that.