Some 64 people were killed in June in the deadliest forest fires in Portugal's recent history.
After several days of calm, a new wave of forest fires has broken out in central Portugal.
More than 2,300 firefighters are battling to stop the flames spreading but strong winds are hampering their efforts.
Civil Protection spokesperson Patricia Gaspar urged the population to stay calm.
The biggest fire is raging around the municipality of Serta in the Castelo Branco region.
Locals are doing their bit to help emergency services combat the flames, even using hosepipes, as seen on pictures broadcast by Portuguese television.
Fire crews are also battling another blaze that started on Sunday afternoon near Coimbra.
In June, amid the deadliest forest fires in Portugal’s recent history, 64 people were killed as they tried to flee in cars or were engulfed in flames in a hilly region some 200 km northeast of Lisbon.
More than 150 others were injured.
Police said that fire was caused by dry lightning strikes and spread so quickly due to an unusually dangerous mix of low humidity, extremely high temperatures and powerful winds.
There are also eucalyptus plantations in the region and the presence of the highly flammable trees was widely seen as a factor in the rapid spread of the fire.
Portugal has now moved to reduce the number of eucalyptus groves as part of forest law reforms.