The air in Athens smells of burning - it's extremely hot and the sky is dark because of the smoke, the BBC's Nikos Papanikolaou reports from Athens
Houses caught alight in Varnavas, about 20 miles north-east of the Greek capital, and a children’s hospital and military medical facility were evacuated at dawn, the fire brigade spokesman says .Around 670 firefighters are battling the flames, which broke out on Sunday afternoon
Greece continues to mount its huge operation to tackle the wildfires as strong winds cause flare-ups in several areas.The BBC World Service's Outside Source has been speaking with two men in the Greek capital, Ioannis and Martin.
"This morning the people of Athens woke up at 4:40am after a message stating that certain areas in the northern suburbs of Athens needed to be evacuated," says Ioannis.
Another resident, Martin, says the wildfire smoke started spreading over the city yesterday afternoon.
"The smoke has been quite bad. A lot of people have been very much rubbing their eyes," he says, "and you can smell the smoke quite badly. We know that it's about 30 minutes drive outside of Athens."
"It's a real tragedy. Every year it's getting hotter and we're getting more and more wildfires," Martin says.
"The truth is that there's not enough firefighters. The equipment they use is from the 1980s. Most of the firefighters are volunteers," he says, "and even though the government says we'll be ready for the next summer, it always appears that they never are.
Firefighters are battling wildfires across north-eastern Attica - with fire fronts ranging from the village of Grammatikos in the north to the suburb of Penteli, just 15km (9 miles) north of Athens.
Strong winds have caused continuous flare-ups in 40 different locations since the early hours of this morning.
The gusts of wind have also blown smoke from the wildfires over Athens - as you can see on the satellite image - where residents report breathing problems and skies filled with smoke.
31 people have been treated for breathing problems by the ambulance services, while the smoke has reached the southern suburbs of Athens.
A human chain of firefighters, volunteer firefighters, police officers and citizens are trying to put down the fire with everything they have - in some cases with tree branches.
But some respite might be coming soon - according to the forecast of the National Observatory of Athens gradual weakening of the winds (and gusts) is expected from 18:00 local time (16:00 GMT).
The governor of Attica, Nikos Chardalias, is holding a meeting this afternoon to discuss the latest wildfire developments.
Representatives of the fire brigade, the mayors and the vice mayors of the affected areas, and representatives from the municipalities of Penteli, Dionysos, Marathonas, Oropos and Rafina-Pikermio, will participate in the meeting to decide the next steps.
In the latest update by the fire brigade spokesperson, Vassilis Vathrakogiannis said the critical fronts are in Ntaou Pentelis, Old and New Penteli, Marathonas to Grammatiko, Dionysos and Patima Vrilission.
The situation looks better in Afidnes and Kalendzi but new flare-ups remain a problem as they create new fronts, which are strengthened by the strong winds.
There are currently 702 firefighters and 119 vehicles and volunteers operating along 17 aircrafts and 18 helicopters, of which three are for coordination. Thirty messages have been sent for area evacuations.
Apart from the houses and the properties, many animals have been burned - including dogs and cats.Nicole says the air became "unbreathable" around her accommodation
I've just been speaking to Nicole Nitu who was staying in the town of Nea Makri before being evacuated this afternoon.
Nicole, who is from the US, describes walking into the garden of her accommodation at 06:30 local time (04:30 GMT) this morning to see smoke less than 100m away.
When looking online for information she says she was reassured the area was safe, before receiving an alert on her phone and evacuating four hours later.
Nicole came to Greece for a work project, with 41 others, including a new-born baby. They are now all waiting at Athens airport.
Another member of the group tells me: "There's no safety plan here, which is just absurd to me."
Unable to change their flights and unsure where else is safe, Nicole says there is not enough clear information from authorities on what to do next.
“We really just want to be told what we need to do and where we need to go," she says.
Help is expected from Italy, France, Romania and the Czech Republic after Greece requested the activation of a European cooperation mechanism.
France will send a Super Puma helicopter tomorrow and Italy a Canadair aircraft, while the Czech Republic is sending 75 firefighters along with 25 vehicles. Assistance from Spain and Turkey is also expected.
The fire has now been burning for more than 24 hours, and the firefighters are still struggling to control it.
Aircrafts only have two hours left until the sunset - after that they must land, and the firefighting operation will be exclusively on the firefighters and the fire trucks on the ground.
A firefighting helicopter had to land earlier due to a mechanical failure.
Residents try to extinguish a wildfire in Marathon, northeast Attica
As we've been reporting, thousands of residents are being evacuated from their homes as a large wildfire spreads towards Athens.
Emergency services say houses caught alight in Varnavas, about 20 miles north-east of the Greek capital.
The country is now on high alert, with high temperatures and strong winds expected to persist over the coming days.
From where I am in the Athens airport terminal building, you can clearly see thick smoke as the fires rage close by in the hills to the north of the airfield.
From a passenger perspective, there's no apparent impact on the airport operation at the moment.
A plane on the runway with smoke billowing in the background
Greece has appealed for international help to fight a severe wildfire that is approaching the northern outskirts of Athens.
Help is expected from Spain, Italy, Turkey and Canada, with France also providing a Super Puma utility helicopter and the Czech Republic sending 75 firefighters and 25 vehicles.
The fire has now been burning for more than 24 hours, and the firefighters are still struggling to control it.
The aircraft have only three hours left until sunset. After that they must land, and the firefighting operation will be continued by the firefighters and trucks on the ground.
We are also hearing that the facilities of the National Observatory of Athens in Penteli are under threat, as the flame continues moving closer to the Greek capital
"It is really hard to breathe when you are there," a Greek journalist has told the BBC's Newshour programme.
"In some areas the air is suffocating and you can see black smoke surrounding houses and neighbourhoods," says Ioannis Papadopoulos, a reporter at the Kathimerini newspaper.
Residents at the front line of the blaze told Papadopoulos that "they live in fear".
"Every summer they worry that a new fire might erupt and that they might be in danger," he says "In a wildfire what is crucial is the first response, how fast the firefighting teams reach the spot and try to suppress the fire," says Papadopoulos.
Whilst firefighters reportedly reached the initial blaze in just five minutes, Papadopoulos says, "what we can see is this was not enough".
"I think the problem is when our firefighting teams have to deal with two or three fires at the same time in different parts of Greece," he adds.
A school in Nea Penteli is now on fire - with residents complaining that there are not enough fire trucks and firefighters to help.
A new message from the 112 Emergency Communications Service has been to the residents of Dionysos to evacuate north-west toward Kifissia.
Houses and properties are on fire in the areas of Ano Vrilissia, Chalandri, and Nea Penteli. Chalandri is 8.8 km away from Athens' centre.
Vrilissia residents are calling for assistance as the flames are really close to their properties.
At the moment 34 aircrafts are operating, however, the operation remains extremely difficult as the winds remain strong and there are constant flare ups.
While fires happen naturally in southern Europe, climate change is making the weather conditions needed for extreme wildfires to spread more likely, external.
Intense, long-lasting heat draws moisture out of the ground and vegetation.
Once ignited – whether by natural or human triggers - these tinder-dry conditions provide fuel for fires to spread at an incredible speed, aided by very strong winds.
The way that humans use land – for example, converting natural vegetation to forest plantations or farmland – is also important in affecting how wildfires spread.
The combined effects of shifting land use and rising temperatures mean extreme wildfires are expected to become more frequent and intense globally in the coming decades, according to the UN Environment Programme, external.
The Greek authorities have officially requested assistance from Croatia and Spain to help with the firefighting operation.
There are explosions from parked cars and fuel tanks in properties which are creating new flare ups - the pressure of the water in the affected areas is getting low.
According to the Fire Risk Prediction Map, issued by the Civil Protection, for tomorrow, Tuesday, 13 August, a very high risk of fire (risk category 4) is predicted for the regions of Attica and Central Greece.
As we've been reporting, Greece has mounted a huge operation to tackle the wildfires that are approaching Athens.Here's a look at some of the firefighters and volunteers battling the flames.A woman uses a bucket of water to extinguish a small fire
17 helicopters and 15 airplanes are making water drops
The sky above Athens has been covered by thick smoke, which, in combination with the high temperatures, makes it difficult to breathe.
65 people were evacuated from a psychiatric hospital in Penteli while power outages in other areas affected by the wildfire make the firefighting operation really difficult.
Local residents have been refusing to evacuate their properties in an attempt to save them - even though the authorities have ordered them to leave.
The smoke makes visibility in the mountainous area really low, making it hard for the aircraft to approach.
As the fire approaches, another hospital has been evacuated - the Amalia Fleming hospital, which is close to Nea Penteli area. The Penteli Children's Hospital was evacuated first thing this morning, as a precaution.
The wildfire frontline in Marathonas looks better than before - the firefighters are optimistic that it would soon be under control, but because the winds keep shifting, it's too early to say that.
