Two new fires broke out Friday afternoon, after firefighters had tamed the several other forest blazes in Portugal, officials said.
A fire in the northern Guarda district spread onto a highway, forcing it to be closed to traffic. Some 95 firefighters, helped by 24 fire trucks, were fighting the fire on two fronts.
Weather services were forecasting a continued dip in temperatures in coming days, although they were expected to soar again next week.
This summer's wildfires have killed 15 people, charred thousands of acres (hectares) of forest and agricultural land, destroyed dozens of houses and driven hundreds from their homes.
Negligence and failure to clean up forests are the main cause of fires, 11 of them firefighters, with only 20 percent of them being caused by arsonists, a Diario de Noticias newspaper report said on Friday. Still, police had so far arrested 126 people on suspicion of arson since the beginning of the year, reports the AP.