ATHENS, Greece (AP) — The smell of smoke and soot permeated Athens as the skies darkened as a wildfire raged northeast of the Greek capital on Sunday.

More than 250 firefighters, 67 fire engines, 12 planes and six helicopters are fighting the fire, which broke out around 3 p.m. local time, about 35 kilometers from Athens.

The flames are moving fast toward Lake Marathon, a key reservoir that supplies water to Athens, fire department spokesman Vassileios Vathrakogiannis said. An unknown number of houses have been damaged.

Vathrakogiannis said winds in the fire area reached gale force and flames were more than 25 meters high. Residents of villages near the fire area were warned to evacuate via emergency text messages.

Another fire that broke out west of Athens has been contained, the spokesman said.

Hot and dry weather, exacerbated by strong winds, increases the risk of forest fires. June and July were the hottest months on record in Greece, which also experienced the hottest winter on record.

Meteorologists and government officials warned of an increased risk of forest fires due to weather conditions from Sunday to Thursday. Half of the country will be on “red alert,” said Vassilis Kikilias, Minister for Climate Crisis and Civil Protection.