Athens  - Firefighters battled raging wildfires approaching Athens for the third straight day Monday, burning houses and forests while forcing thousands to flee their towns.

Easing winds in the early hours offered firefighters some hope as water-dropping planes and helicopters resumed operations at first light, assisted by aircraft from Italy, France and Cyprus. More than 2,000 firefighters, soldiers and volunteers are fighting the fires on the ground.

Officials warned that the fires still threatened the heavily populated northern coastal towns of Nea Makri, Dionysos and nearby Marathonas.

"There are fewer fronts but the blaze is still developing," Fire Brigade Chief Giannis Kappakis said.

Three days of wildfires destroyed several homes and thousands of acres of forest and olive groves but there were no reports of deaths or serious injury.

In the area of Nea Makri, firefighters battled throughout the night to contain the fire that ripped through hillsides and forced the evacuation of a dozen nuns from a nearby Christian Orthodox monastery.

Over the past few days evacuations of entire towns were ordered with residents seen fleeing in cars, by motorcycle or on foot, including the more than 10,000 inhabitants of Aghios Stefanos after flames gathered dangerously close to the main square.

Many Athenians who ignored calls to evacuate their neighborhoods could be seen fighting the flames outside their homes with water hoses and branches.

Others, armed with shovels and buckets, worked side by side with firefighters and soldiers throughout the night to battle the fires.

Television reports continuously showed panicked residents pleading for firefighters and aircraft that were nowhere to be seen.

Officials have not officially said what started the fire but forest fires have become more frequent in Greece in recent summers, triggered by high temperatures and drought but also arson, often by land developers.

The fires broke out late Friday just north of Marathonas and quickly spread over Mount Penteli, fanned by the winds to an area more than 40 kilometres wide, damaging homes and burning thousands of acres of forest and olives groves.

A state of emergency was declared in greater Athens almost immediately and critics say the poor handling of the fires by the conservative government resembled those which struck the island of Evia and the Peloponnese in 2007, killing more than 80 people.

Six major fires were still burning early on Monday across Greece, including on the islands of Evia and Skyros. (dpa)