|A firefighter stands in the middle of a road near flames blazing near the village of Sanguinheira, in Macao, central Portugal, on Jul 25, 2017. (AFP/PATRICIA DE MELO MOREIRA)|
Weather conditions will be "especially favourable for wildfires" until Sunday, with strong winds and temperatures of up to 39 degrees Celsius forecast, civil protection agency spokeswoman Patricia Gaspar told a news conference.
Morocco sent a water-dropping plane and neighbouring Spain sent two to help firefighters battle the flames, she added.
The fires come after more than 60 people were killed in June, and more than 250 injured, in a giant blaze at Pedrogao Grande in central Portugal that raged for five days.
Eleven fires were still out of control as of 11.00pm (2100 GMT) on Thursday while the rest had been tamed or were being dampened down, the civil protection agency said on its website.
Some 800 firefighters backed by 250 vehicles were at the scene of the biggest blaze in a forest near the central town of Abrantes.
The fire had reached the outskirts of the city, Abrantes mayor Maria do Ceu Albuquerque said. "The night is going to be very difficult," she told Portuguese media.
Officials evacuated four nearby villages because of the threat from the flames and smoke.
"It has burned all day. It started up high and the flames made a complete tour," Matilde Simao, a resident of evacuated village Pucarica, told AFP.
Firefighters said low air humidity levels and strong winds, which frequently changed direction, were complicating the battle against the blaze.
"There are people setting fires, bad people. It is the only explanation that I can see, there is no other," said Maria Conceicao, another resident of Pucarica.
Local residents used garden hoses and plastic buckets full of water to help firefighters put out the flames, television images showed.
Another fire near the northern village of Mealhada forced the closure of a 30-kilometre stretch of the A1 highway linking Lisbon and Porto, Portugal's two largest cities.
A blaze near the southern city of Grandola forced the closure of the railway linking Lisbon to the southern province of the Algarve, a popular European beach destination.
Police said they had arrested a 61-year-old man who is suspected of having started a fire near the central village of Lordelo.
The president of the Portuguese Firefighters' League, Jaime Marta Soares, told private television SIC he believed more than 80 percent of wildfires in Portugal had a "criminal origin".
After an uncommonly dry winter and spring, almost 79 per cent of the Portuguese mainland was enduring extreme or severe drought at the end of July, according to the national weather office.
Dry conditions were also fuelling a wildfire on France's Mediterranean coast. About 200 firefighters backed by six water-dropping aircraft battled a blaze in Port-de-Bouc west of Marseille which was threatening built up areas, local firefighters said.