ATHENS, Greece — Greek authorities have evacuated several areas north of Athens as a wildfire swept through a hillside forest and threatened homes despite a large operation mounted by firefighters.

Five water-dropping planes and four helicopters were being used Tuesday to fight the blaze outside the Stamata area, 30 kilometers (18 miles) northeast of the capital.

Residents in the area received cellphone alerts and were being urged to keep doors and windows closed to avoid exposure to smoke and prevent hazardous sparks from blowing inside homes.

Dozens of firefighters were also deployed on the ground to try and contain the fire, which sent smoke over Athens.