Greek firefighters joined by colleagues from Israel and around Europe are using water-dropping planes and helicopters to try to gain the upper hand on wildfires burning for a fifth day.
Numerous fires in the mountainous southern peninsula of Peloponnese are not yet under control Tuesday.
Police have charged seven people with arson and are offering a $1.4 million reward for information leading to more arrests.
A Greek prosecutor is checking whether police can use the broader powers of anti-terrorism and organized crime laws to investigate arson suspects.
The fires have killed at least 63 people since last Thursday and wiped out thousands of hectares of forests and olive groves. Hundreds of villages have been evacuated.
Some local authorities blame the blazes on rogue land developers who they suspect of burning down forests to clear the land for construction.
Some opposition politicians and Athens newspapers have accused the government of incompetence in fighting the fires. Parliamentary elections are scheduled for September 16.
Some information for this report was provided by AFP and AP.
