The worst fire scorched Vila Nova de Cerveira in Minho region and continued to spread on Saturday due to "difficult to access terrain, wind, high temperatures and the ongoing drought," a fire service spokesman said.
After having escaped relatively unscathed by wildfires last year, Portugal has been hit by major forest fires this summer.
Nearly 80 percent of the country's territory is considered to be in a severe drought, a situation that is likely to get worse in August, according to the Portuguese meteorological agency IPMA.
Another major fire is raging fewer than 50 kilometres (31 miles) away in Moncao despite the efforts of some 100 firefighters.
Portugal also contributed about 100 firefighters and dozens of vehicles to the battle against a wildfire in Estremadura in western Spain that ravaged nearly 6,500 hectares (16,000 acres), but which was brought under control Sunday.
Some 2,400 residents who were evacuated from their homes were allowed to return, and roads that were closed have reopened, Spanish officials said.
Wildfires have destroyed more than 54,000 hectares of agricultural and forest land in Spain this year, exceeding the area burned over the last two years combined, according to the agriculture ministry.
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