But Paulo Fernandes, a forest researcher at Portugal's Tras-os-Montes e Alto Douro University, notes that around 90 percent of landowners have smallholdings, making it hard for authorities to oversee them all. The Civil Protection Agency said about 1,200 firefighters.
As water-bombing planes made regular passes over the flames, there were growing suggestions that forestry practices and outdated emergency planning might have contributed to the disaster.
Coutinho tells The Associated Press that "it could have been a unusual coincidence, with a plane passing over and an explosion occurring on the ground at the same time".
Portuguese media also reported the crash, based on a variety of sources.
"There are already some areas where the fires are contained and being extinguished", he told reporters.
Portugal's Civil Protection agency said the town of Góis, some 40 km from the forest fire's epicenter in the Pedrógão Grande region was now the most unsafe zone in the area affected by the fire, Efe news reported.
Reinforcements are due to arrive Monday, including more water-dropping planes from Spain, France and Italy as part of a European Union cooperation program.
Yesterday 1,150 firefighters and almost 400 vehicles were still battling the fires, helped from the air by water-bombing planes including some sent from France, Italy and Spain.
On Tuesday night, the authorities evacuated more villages around Gois, to the north of Pedrogão Grande, as wildfires which appeared to be under control flared up again. There, about 1,100 firefighters supported by 11 water-dropping aircraft are battling the flames, which officials say they expect to extinguish by the end of the day.
At least 64 people have died and over 150 injured in the blazes, which broke out in Pedrogao Grande over the weekend and spread quickly to other areas.
A spokesman for Spain's Ministry of Defense said it had not lost a plane, denying earlier reports that a Spanish water-dropping plane had crashed.
It is possible that the lady saw an aircraft and the unrelated explosion, which appeared to be associated with the plane. Her office immediately sent a crash investigation team to the area.
But in a weird sequence of events, officials with the Portuguese government and the Civil Protection Agency said they could not confirm a crash had taken place.
"It is all very volatile, the fire may be brought under control but the winds can change", she said.
"The fire is no longer progressing", Civil Protection Agency spokesman Vitor Vaz Pinto said, adding that hundreds of firefighters would remain on the scene to prevent it from reigniting. More than 2,000 firefighters in Portugal battled Monday to contain major wildfires in the central region of the country, where one blaze killed dozens of people, while authorities came under mounting criticism for not doing more to prevent the tragedy.
The wildfires in Portugal that killed more than 60 could have been started by arsonists rather than lightning, the head of the country's firefighters' association said Wednesday.
The death toll was raised from 63 to 64 late Monday.
Portuguese Prime Minister Antonio Costa has questioned why the emergency services did not close the road.