The Hellenic Police and the Fire Service said they have launched a joint investigation after at least 15 fires were reported in 48 hours in the broader Evros region.
Meanwhile on Wednesday, dozens of firefighters continued to battle a large blaze in protected forestland in the northeastern region of Evros that broke out on Tuesday afternoon.
More than 100 firefighters were sent to the area of Melia near the town of Alexandroupoli, along with 24 trucks, two water-dumping helicopters and two airplanes.
Municipal crews and dozens of volunteers were also assisting in the firefighting effort, which was hampered by strong winds fanning the flames.
Alexandroupoli forestry chief Giorgos Pistolas told the Athens-Macedonian News Agency that firefighters were able to prevent the flames from reaching the village of Nipsa overnight.
He said that strong winds continued to hamper efforts to bring the blaze under control.
Firefighters were also taxed by blazes on the Ionian islands of Zakynthos and Cephalonia, with 26 firefighters sent to the blaze on forestland in Agia Marina on Zakynthos and 17 to a forest in Myrtos on Cephalonia.