Greek firefighters battled over a dozen wildfires for a fourth day Friday but officials said the situation was improving.
"Generally we are doing well, our only major front is in (the southern region of) Achaia in the Peloponnese," Greek fire brigade spokesman Yiannis Stamoulis told AFP.
The arrival of Russian reinforcements in the form of water-dousing aircraft was postponed until Saturday evening after initially being expected Friday.
Two Russian firefighting helicopters will be sent to the northern city of Salonika and will be deployed depending on need, a defence ministry source said.
Many areas in northern Greece were still on fire Friday, but the main front remained in Achaia where a blaze has destroyed around 100 homes and properties since Tuesday, killing three elderly villagers who did not flee the area.
"Around 15,000 hectares (37,000 acres) are estimated to have been burned," western Greece regional supervisor Spyros Spyridonos told NET state television.
Fires were raging from the northern regions of Ioannina, Kastoria, Florina, Pieria, Kozani and Salonika to the southern region of Messinia.
Firefighters had trouble reaching two of the blazes in Ioannina and Kastoria because of landmines dating from World War II and the Greek Civil War over 60 years ago.
Greece's fire brigade has been fighting hundreds of blazes in the past month, fanned by high winds and an earlier heatwave that authorities described as the longest Greece has experienced in over 100 years.
One of the larger fires destroyed 5,600 hectares of forest on Mount Parnitha overlooking Athens, including over a third of a national park that was supposedly among Greece's best protected.
Five firefighters have died this past month. Two water-bomber pilots were killed when their aircraft crashed battling a blaze on the island of Evia and three part-time firemen died in a wildfire on the island of Crete.
