Thousands of people fled their homes around Athens on Monday, including in the historic town of Marathon, as strong winds fanned a wall of wildfire flames closer to the Greek capital.
A 30-kilometre (20-mile) long frontline of fires, more than 25 metres (80 feet) high in places, was moving towards Athens, the ERT public broadcaster reported.
Nearly 700 firefighters and over 30 aircraft battled the blazes that had advanced into the city's outer suburbs near Mount Pentelikon.
Authorities opened the Olympic stadium in northern Athens and other stadiums to house those fleeing. Three major hospitals have been placed on standby.
One firefighter suffered serious burns, another was hospitalised with breathing trouble and 13 other people were treated for milder respiratory problems, fire brigade spokesman Vassilis Vathrakogiannis said.
Halandri became the latest suburban municipality to order a partial evacuation of areas threatened by the flames.
"Because of the direction of the wind we have decided on a precautionary evacuation," its mayor Simos Roussos told ERT. "The fire is very close."
Television footage showed flames burning among homes in Nea Penteli, a leafy Athens suburb which also told residents to relocate.
Several smaller communities and towns, including Marathon, which gave the Olympic long distance race its name, started to evacuate on Sunday.
"We are facing a biblical catastrophe," said Marathon's mayor Stergios Tsirkas. "Our whole town is engulfed in flames," he told the Skai television channel.
Smoke drifted through central Athens as thick grey clouds engulfed Mount Pentelikon, which looms above the capital and is known for producing the marble used in the Acropolis and other ancient buildings.
"Civil protection forces battled hard throughout the night, but despite superhuman efforts, the fire evolved rapidly," Vathrakogiannis said.
The wind had rekindled the fire in 40 different locations on Monday, he said.
A children's hospital and a military medical facility in Penteli were evacuated at dawn, Vathrakogiannis said.
The destruction revived memories of the Mati disaster, the coastal area near Marathon where 104 people died in July 2018 in a tragedy later blamed on evacuation delays and errors.
The summer wildfire season in Greece this year has seen dozens of daily blazes after the Mediterranean country recorded its warmest winter and the hottest June and July since reliable data collection began in 1960.
Temperatures around Athens are forecast to peak at 39 degrees Celsius (102 degrees Fahrenheit) on Monday, with wind gusts of up to 50 kilometres (31 miles) per hour.
'Engulfed in flames'
"Forest fire near you. Follow the instructions of the authorities," said SMS messages sent to people in the Attica region, indicating in which direction to flee.
Civil Protection Minister Vassilis Kikilias issued a warning Saturday that half the country faced a high-risk of fires due to high temperatures, strong winds and drought conditions.
On Monday he said that a fire that broke out on Sunday near the town of Varnavas spread even though a water-bombing aircraft reached the area in just five minutes.
"We're working 24-hour shifts, all of us," said fireman Marinos Peristeropoulos.
"The fire spread very quickly because of the strong wind," he told AFP near one of the hotspots in Grammatiko.
Scientists say that human-induced fossil fuel emissions are worsening the length, frequency and intensity of heatwaves across the world.
Rising temperatures are leading to longer wildfire seasons and increasing the area burnt in the flames, according to the UN Intergovernmental Panel on Climate Change.
Other parts of Europe are also struggling with high temperatures.
Temperatures in parts of France rose above 40 Celsius on Sunday. In Rome, temperatures were expected to reach 38 Celsius Monday and remain around 36 Celsius this week.
In the Netherlands, temperatures between 32 and 35 degrees Celsius are expected.