The Pedrógão Grande fire is one of more than 60 fires that broke out overnight throughout the country, the BBC reported, and according to the New York Times, an additional 11 areas were under surveillance for an "extreme fire risk".
The mayor of Pedrogao Grande, Valdemar Alves, said that some villages had been "completely surrounded by flames" as quoted in the Publico newspaper.
Smoke rises above trees during a forest fire in Pedrogao Grande, Leiria District, Portugal, June 17, 2017.
The expanse of wooded hills in the area north of Lisbon, which 24 hours before had glowed bright green with eucalyptus plants and pine trees, was gutted by the flames.
Juncker wrote in the letter that "Our thoughts are with all the victims, their families and all the fearless soldiers of peace that in a very hard terrain and under challenging circumstances continue to fight this bad fire". "I never thought it would come to this side", she said Sunday.
The Correio do Manhã warned that many areas hit by the fire had not yet been reached by authorities, so the death toll was likely to increase.
RTP showed terrifying images of several people on a road trying to escape the intense smoke that had reduced visibility to a question of a few meters (yards). A young man shared a bottle of water with a distraught woman as she stumbled down the road.
Secretary of State for the Interior Jorge Gomes said 62 people burned to death, mostly trapped in their cars engulfed by flames.
"It is the greatest tragedy of human lives that we've witnessed in Portugal in years", Prime Minister Antonio Costa said in televised comments.
"The smoke cloud is very low, which does not allow helicopters and fire planes to work efficiently ... but we're doing everything possible and impossible to put out this fire", Gomes said, adding that no villages were now at risk. Citing the high temperatures, it said that all outdoor fires were prohibited. France was also sending three aircraft. "In addition, Spain has also sent aircraft on a bilateral basis".
Spanish Prime Minister Mariano Rajoy tweeted that he is "overwhelmed by the tragedy at Pedrogao Grande".
Pope Francis called on worshippers in Saint Peter's Square in the Vatican to pray for those affected by the "devastating fire" in Portugal.
Portuguese President Marcelo Rebelo de Sousa visited the site of the tragedy during the night and later expressed his condolences.