Growing forest blaze swept through Athens suburbs, forcing many to flee their homes.
The fire, fanned by strong winds, started on Monday, but had seemed under control.
The wildfire has approached the last remaining pine forests near Athens, putting local homes at risk.
The village of Vilia, about 50 kilometers northwest of Athens, and another six villages, were evacuated, along with a nursing home. The fire reached the road towards Vilia and encircled the village.
More than 400 fire-fighters, including 143 from Poland, along with volunteers battled the blaze.
Fire-fighters managed to stop a fire from engulfing one house. It was not clear if any homes were damaged in the blaze.
Greece has been facing what has been described as its worst heatwave for more than three decades.
Athens saw temperatures climb as high as 45 degrees Celsius (113 degrees Fahrenheit). Forecasters predict they will reach 40 C later next week.
Fresh fires broke out late over the past few weeks. Meanwhile, strong winds and blistering heat continued to complicate the efforts of rescue crews.
“It is a large fire, and it will take a lot of work to get this under control,” more excellent Athens regional governor George Patoulis said.
“People in the area should be on stand-by. We are asking members of the public in the fire-affected areas to keep the windows of their homes closed because the smoke is very dense.”
As of Wednesday morning, authorities reported no serious injuries from the Athens wildfires. The fires are linked directly to climate change by government officials.
Greek Civil Protection chief Nikos Hardalias said the fire was “hazardous” and was being exacerbated by strong winds and blistering heat.
“There are crucial hours,” Hardalias said. “Our country is undergoing one of the worst heat waves of the past 40 years.”
“Because the heatwave will continue in the coming days, please avoid any activity that could spark a fire,” he added.