Nearly 3,000 firefighters battled 80 wildfires raging across Portugal on Thursday, civil protection officials said.
Weather conditions will be "especially favourable for wildfires" until Sunday, with strong winds and temperatures up to 39 degrees Celsius (102 Fahrenheit) forecast, Portuguese civil protection agency spokeswoman Patricia Gaspar told a news conference.
Some 650 firefighters backed by nine water-dropping aircraft and over 200 vehicles were at the scene of the biggest blaze in a forest near the central town of Abrantes.
The fire has destroyed several holiday homes and forced the closure of a number of local roads, Abrantes mayor Maria do Ceu Albuquerque said.
"The battle against the fire is very difficult, there are two active fronts that are burning with great intensity. Temperatures are very high, the situation is far from being brought under control," she told news radio TSF.
Officials evacuated four nearby villages because of the threat from the flames and smoke.
Local residents used garden hoses and plastic buckets full of water to help firefighters put out the flames, images broadcast on Portuguese television showed.
Firefighters said low air humidity levels and strong winds, which frequently changed direction, were complicating the battle against the blaze.
Another wildfire near the northern village of Mealhada forced the closure of a 30-kilometre (18-mile) stretch of the A1 highway linking Lisbon and Porto, Portugal's two largest cities.
Police said they had arrested a 61-year-old man who is suspected of having started a fire near the central village of Lordelo.
After an uncommonly dry winter and spring, almost 79 percent of the Portuguese mainland was enduring extreme or severe drought at the end of July, according to the national weather office.
In June over 60 people were killed, and more than 250 were injured, in a giant wildfire at Pedrogao Grande in central Portugal that raged for five days.