A raging forest fire in central Portugal sent flames sweeping over roads, killing at least 61 people, many of them trapped in their cars as they tried to flee.
The country's prime minister called it "the biggest tragedy" that Portugal has experienced in decades and declared three days of national mourning.
A huge wall of thick smoke and bright red flames towered over the top of trees in the forested Pedrogao Grande area some 150 kilometres northeast of Lisbon where a lightning strike was believed to have sparked the blaze Saturday.
Investigators found a tree that was hit during a "dry thunderstorm," the head of the national judicial police told Portuguese media.
At least four other significant wildfires affected different areas of the country overnight but the one in Pedrogao Grande was responsible for all the deaths.
"The dimensions of this fire have caused a human tragedy beyond any in our memory," said Prime Minister Antonio Costa.
"Something extraordinary has taken place and we have to wait for technicians to properly determine its causes."
More than 350 soldiers overnight joined the 700 firefighters who have been struggling to put out the blaze.
Authorities say temperatures as high as 40 degrees Celsius in the area in recent days might have also played a part in the inferno.