At least 27 people have died and hundreds have fled from wildfires that spread and caused widespread destruction across the Greek mainland and islands, radio reports said on Saturday.
The authorities fear that the death toll will rise as hundreds were trapped in remote villages encircled by flames on the Peloponnese peninsula.
"It's terrible. I have never experienced anything like this. We keep finding charred bodies lying on the streets. There's a mother with her four children here," the president of the Greek journalists' association, Panos Sombolos, said in a television report from the village of Makitos in the western Peloponnese.
Almost all Greek newspapers spoke of "apocalyptic images" in their on Saturday morning editions.
At first light planes and helicopters were sent to the worst hit region of Zacharo town in the western Peloponnese to drop water on the flames.
The Greek government Friday asked the European Union for support in fighting the wildfires.
The fire service said that fires had broken out in more than 170 places in almost every region in the south of the country.
Several hundred people were evacuated with small ferries from the seaside town of Nea Styra on the second largest Greek island Euboea.
Hundreds fled in panic from vacation quarters in the region around Nea Styra in the south of the island. The smoke carried to the eastern suburbs of Athens.
Firemen were deployed in Athens to quench a fire in a park in Galatsi.
Temperatures soared to 40 degrees in southern Greece, inching down into the 30s at night in Athens.
A number of villages were evacuated on the Peloponnese peninsula. A massive fire raged out of control near the southern Greek port of Kalamata. Other fires burned near Sparta, Corinth and Tripolis.
A state of emergency has been called in the prefectures of Messina, Lakonia and Ilia.
Earlier, the flames had destroyed several houses in three communities on mountain Taygetos in the east of Athens as it burned overnight on Thursday.
Thick black smoke could be seen for kilometres spreading over the whole of the Gulf of Messina at the southwestern tip of the Peloponnese peninsula.
Prime Minister Kostas Karamanlis sent reinforcements from northern Greece to help out with the fire-fighting efforts.
A mobile army surgical hospital was deployed to Zacharo in the worst hit region as hundreds of soldiers arrived to help people in need, national broadcaster NET reported.
After several attempts, Karamanlis finally made it to Zacharo on Friday evening, promising financial aid for everyone affected by the fires, radio reports said.
"These hours are difficult for us all. They are the hours for taking charge and fighting.
"Hundreds of fire fighters, soldiers, volunteers and simple people are risking their lives to fight the flames.
"We are here. We are standing by them. We trust in them," the prime minister said in a televised speech.