A firefighter coordinates the fight against a wildfire that has forced the evacuation of thousands of people around Athens
A firefighter coordinates the fight against a wildfire that has forced the evacuation of thousands of people around Athens AFP

A massive wildfire in Athens' northeastern suburbs on Monday forced thousands of residents to flee their homes and sparked a Greek government appeal for international help.

In unprecedented scenes in the Greek capital, residents wearing masks against the choking smoke were desperately dousing their homes with water hoses in the leafy suburbs of Nea and Palaia Penteli and Vrilissia to protect them from fire.

"(It's) the first time ever the fire has come here," said Melina Kritseli, 40, a civil servant living in a two-storey white house in Patima Halandriou, another Athens suburb that was evacuated.

"I took my children to a friend's house to be safe," she told AFP as her husband hosed the ground and grass outside their house.

Television footage showed several charred cars and the roofs of stately homes burning as water-bombing helicopters roared overhead.

Smoke drifted through central Athens as thick grey clouds engulfed Mount Pentelikon, which is known for yielding the marble used in the Acropolis and other ancient buildings.

The fire gutted a sports hall in Nea Penteli and many homes and businesses in the surrounding area.

The National Observatory, Greece's foremost institute monitoring natural hazards, narrowly escaped.

The Observatory website meteo.gr said 10,000 hectares (24,700 acres) had been devastated by midday Monday.

Greece on Monday formally called for EU assistance.

"The EU civil protection mechanism was activated upon request of the Greek authorities," EU spokesman Balazs Ujvari said in a statement.

He added that Italy, France, the Czech Republic and Romania were sending units to help.

"We stand with Greece as it battles devastating fires," EU commission chief Ursula von der Leyen wrote on X.

Prime Minister Kyriakos Mitsotakis had earlier cut short a vacation to Crete and returned to the capital Sunday.

The wildfire started on Sunday afternoon in the town of Varnavas, some 35 kilometres (22 miles) northeast of Athens.

Fanned by strong winds, it grew to a 30-kilometre long frontline of flames, more than 25 metres (80 feet) high in places, according to state TV ERT.

"I heard my animals bleating and dying," Dimitris Megagiannis, a goat herder near Palaia Penteli, told Mega TV station.

The fire department said over 700 firefighters with nearly 200 fire engines were trying to contain the fire, but dozens of water-bombing aircraft had to retire after dark.

Authorities opened the Olympic stadium in northern Athens and other sports facilities to house thousands of people evacuated from the path of the blaze. Three major hospitals have been placed on standby.

One firefighter suffered serious burns and another was hospitalised with breathing trouble, fire brigade spokesman Vassilis Vathrakogiannis said.

The health ministry said 66 people had been treated for injuries related to the fire since Sunday.

Several smaller communities and towns, including Marathon, started to evacuate on Sunday.

Several small clinics and hospitals in the area followed suit.

"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.

The destruction revived memories of the disaster in Mati, 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.

The National Observatory said temperatures of up to 38 degrees Celsius (100 Fahrenheit) are expected in Athens on Tuesday, with winds of up to 39 kilometres (24 miles) per hour.

"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 the fire had spread even though a water-bombing aircraft reached the area within 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.

Parts of France rose above 40C on Sunday. In Rome, temperatures were forecast to reach 38C Monday and remain around 36C this week.

Firefighters sprayed water to try to extinguish a wildfire in Grammatikos region
Firefighters sprayed water to try to extinguish a wildfire in Grammatikos region AFP
The Parthenon temple atop the Acropolis hill was surrounded by a cloud of smoke from a wildfire threatening the Athens suburbs
The Parthenon temple atop the Acropolis hill was surrounded by a cloud of smoke from a wildfire threatening the Athens suburbs AFP
Firefighters hosing a wildfire in Dione outside Athens
Firefighters hosing a wildfire in Dione outside Athens AFP
Local residents watch a wildfire in Dione outside Athens
Local residents watch a wildfire in Dione outside Athens AFP
A man gets into his car to escape approaching flames as a wildfire blazes outside Athens
A man gets into his car to escape approaching flames as a wildfire blazes outside Athens AFP