More than 100 wildfires have ripped through Portugal killing seven people.
Portuguese Prime Minister Luis Montenegro declared a “state of calamity” and dispatched thousands of firefighters to tackle the blazes.
Portuguese national police said that they have arrested seven men suspected of having started wildfires in recent days.
Mr Montenegro told the nation in a televised address: “We are well aware that these difficult hours are not over yet.
“We have to continue to give everything we have and ask for help from our partners and friends so that we can reinforce the protection of our people and property.”
The hot, dry conditions behind the outbreaks in Portugal coincided this week with flooding in central Europe.
The European Union said on Wednesday that that recent wildfires and extreme weather are proof of a “climate breakdown”.
Fellow European Union members Spain, France, Italy and Greece have committed two water-dropping aircraft each to help Portuguese firefighters.
Spain’s military is also sending 240 soldiers and vehicles from its emergency response battalions specialised in combating fires across the border to its neighbour.
Mr Montenegro made a special call for security forces to pursue both arsonists and any individuals who started a fire out of negligence.
Among the hardest-hit areas is the district of Aveiro, south of the northern city of Porto, but several major blazes were also raging out of control in other wooded areas.
Authorities have yet to release figures for property damage or the number of evacuees, but Portuguese state broadcaster RTP has shown charred houses in rural villages and local residents trying to battle flames with buckets of water, hoses, and even large tree branches.
Other televised images showed visibility reduced to a few metres as orange smoke enveloped the terrain.
Three firefighters died in their vehicle on Tuesday, while another had succumbed to what authorities called a “sudden illness” while on duty over the weekend. Three civilians have also died, according to civil protection authorities.
Portugal was devastated by massive fires in 2017 that killed more than 120 people.
