About 700 firefighters were battling blazes in northern and central Portugal on Monday, with two people arrested on suspicion of starting fires, officials said.
The firefighters were being supported by five French and Croatian aircraft.
“This evening we have 14 major fires under way in the north, in particular in the Porto, Viseu, Castelo Branco and Braga districts”, civil protection spokesman Carlos Guerra told AFP.
Police announced that a 40-year-old woman and a 12-year-old boy were arrested Monday on suspicion of starting separate fires in central and northern Portugal.
“The wind blows with such an intensity that it constitutes the main obstacle to firefighters,” said Jose Bismarck, commander of the firefighters in Aveiro.
Portugal had enjoyed a lull in its battle against forest fires since Friday after mastering blazes in the mountainous region of Caramulo where three firefighters have been killed.
“We thought we were in a war zone,” Marta Rosa, a young resident of the village of Caramulo, told AFP.
“The firefighters who came to save the house of my parents told me it was like a firestorm.”
The period of respite came after “less intense winds on Saturday night and Sunday”, said Guerra, from the national authority of civil protection.
However, he noted 313 new fires had been recorded by the authorities since Saturday.
A desperate Portugal had requested reinforcements from its European neighbours. Spain, France and Croatia had responded, sending aircraft to help fight the blazes.
Portuguese firefighters remain on alert as the weather forecast predicts more high temperatures and strong winds until Tuesday.