Traffic was suspended along a main highway connecting Koropi to Athens suburbs. One storage facility was burned and flames crept into a boat dry dock and across fields of dry grass and olive trees, images on local TV showed. Authorities evacuated two nearby villages.

There were no reports of deaths or injuries. A fire service official said the intensity of the blaze had eased but that it was not out. High winds carry sparks that can quickly open new fronts, the official said.

"It's a very difficult day today. We have a new fire breaking out every 10 minutes," Fire Service spokesman Vassilis Vathrakogiannis said in a televised message.

Wildfires are common in the Mediterranean nation but they have become more devastating as summers have become hotter and drier, which scientists relate to climate change.

On Tuesday more than 40 fires broke out across the country, the fire service said. On Wednesday hundreds of firefighters were deployed to at least six blazes. High winds and hot temperatures will extend the risk into Thursday, it said.

It was not immediately clear what caused the fire near Athens. Much of the area has had no rain for weeks, leaving large areas bone dry. Four firefighting planes, six helicopters, dozens of fire engines and more than 50 firefighters were dispatched to the scene, the fire service official said.

Volunteers and professional firefighters dragged hoses over blackened fields in 35 degree Celsius (95 degrees Fahrenheit) heat. Smoke filled the sky and was driven sideways by strong wind gusts.

"I saved my home at the last moment. It all happened so fast," a resident whose face was blackened by smoke told local Skai TV channel.

After forest fires last year forced 19,000 people to flee the island of Rhodes and killed 20 in the northern mainland, Greece has scaled up its preparations this year by hiring more staff and increasing training.