ATHENS, Greece — A large wildfire broke out Thursday south of Athens, prompting authorities to send phone alerts urging the evacuation of five communities near the blaze as temperatures approached 40 degrees Celsius (104 Fahrenheit) in Greece’s first heat wave of the summer.

Eight water-dropping planes and five helicopters provided air support to 90 firefighters battling the blaze in the Palaia Fokaia seaside area south of Athens, the fire department said. The fire, which reportedly broke out within a populated area, was fanned by strong winds, sending plumes of smoke fanning out across the sky. Footage from local television showed at least one house burning.

The coast guard said two patrol boats and nine private vessels were on standby in the Palaia Fokaia area in case an evacuation by sea became necessary, while a lifeboat was also on its way.

“We’re telling people to leave their homes,” local town councilor Apostolos Papadakis said on Greece’s state-run ERT television.

The entire wider Athens area, as well as several Aegean islands, were on Level 4 of a 5-level scale for the danger of wildfires due to the weather conditions, with the heat wave expected to last until the weekend.

Earlier in the week, hundreds of firefighters took four days to bring a major wildfire under control on the eastern Aegean island of Chios. More than a dozen evacuation orders had been issued for Chios, where the flames devoured forest and farmland. The fire department said one woman had been arrested on suspicion of having contributed to that fire’s start – reportedly by discarding a cigarette.

Wildfires are frequent in Greece during its hot, dry summers. In 2018, a massive fire swept through the seaside town of Mati, east of Athens, trapping people in their homes and on roads as they tried to flee. More than 100 died, including some who drowned trying to swim away from the flames.