PEDROGAO GRANDE, Portugal — A raging forest fire in central Portugal killed at least 62 people as they desperately tried to flee, charring cars and trucks as it swept over roads.

The disaster – the worst tragedy Portugal has experienced in decades – shook the nation, with the president declaring that the country’s pain “knows no end.”

Almost 24 hours after the deaths Saturday night, fires were still churning across the forested hillsides of central Portugal. Police and firefighters were searching charred areas of the forest and isolated homes, looking for more bodies.

“It is a time of pain but also … a time to carry on the fight” against the flames, President Marcelo Rebelo de Sousa told the nation in a televised address Sunday evening after the government declared three days of national mourning.

A huge wall of thick smoke and bright red flames towered over the tops of trees in the forested Pedrogao Grande area, 95 miles 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 said.

Dry thunderstorms are frequent when falling water evaporates before reaching the ground because of high temperatures. Portugal is prone to forest fires in the dry summer months and temperatures as high as as 104 degrees Fahrenheit hit the area in recent days.

At least four other significant wildfires were burning Sunday elsewhere in Portugal 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,” Prime Minister Antonio Costa told reporters as he arrived at the scene Sunday. “Something extraordinary has taken place and we have to wait for experts to properly determine its causes.”

He said the death toll was lowered to 61 from 62 because one person had been counted twice. However, he said “there’s no point in feeling joyful for that, because surely we will find more victims as we progress.”

Interior Ministry official Jorge Gomes said firefighting crews were having difficulties battling the fire, which was “very intense” in at least two of its four fronts. He said authorities were worried about strong winds that could help spread the blaze further.

More than 350 soldiers Sunday joined the 700 firefighters who have been struggling to put out the blaze, schools in the area were closed until further notice and outdoor fires were banned.

The forest fire deaths were the biggest in memory in Portugal, which saw 25 Portuguese soldiers die fighting wildfires in 1966. Last August, an outbreak of fires across Portugal killed four people, including three on the island of Madeira, and destroyed huge areas of forest.

“This is a region that has had fires because of its forests, but we cannot remember a tragedy of these proportions,” said Valdemar Alves, the mayor of Pedrogao Grande. “I am completely stunned by the number of deaths.”

State broadcaster RTP showed images of people on a road trying to the intense smoke that had reduced visibility to a few yards.