Authorities are blaming arson for some 17 fires which have caused multiple deaths in the northwestern region: three fatalities were confirmed by Monday morning, and at lunchtime it was confirmed that the fires had claimed a fourth victim, a man in his 70s who fell from an embankment while trying to battle a fire approaching his and a neighbour's house in Vigo.
"They are absolutely intentional fires, premeditated, caused by people who know what they are doing," the head of the Galician regional government, Alberto Nuñez Feijoo, said.
Fifteen separate wildfires which posed a risk to built up areas were raging across the region of Galicia. On Monday, the "situation remained very worrying", Feijoo said, adding that firefighters along with soldiers and locals were battling the flames.
Spanish Interior Minister Juan Ignacio Zoido said in a tweet that "several people have been identified in connection to the fires in Galicia".
The flames were being fanned by wind gusts of up to 90 kilometres (55 miles) per hour as Hurricane Ophelia moved north off the coast of Spain towards Ireland, he told private broadcaster La Sexta.
Más de 600 efectivos de la UME están desplegados en Galicia y Asturias para colaborar en la extinción de incendios.— Ministerio Defensa (@Defensagob) October 15, 2017
Mucho ánimo compañeros! pic.twitter.com/R09SRUsamc
"The situation is critical," he said.
Feijoo said "thousands" of firefighters, soldiers and locals were battling the blazes.
"We have not had a situation like this in the past decade. We have never deployed so many means at this time of the year," he said.
Prime Minister Mariano Rajoy, who is from Galicia, expressed his condolences to the victims in a Twitter message.
Mi pésame por los fallecidos en los incendios en Galicia. Gracias a todos los que trabajan en su extinción y en atender a la población. MR— Mariano Rajoy Brey (@marianorajoy) October 15, 2017
Five wildfires were raging near Vigo, Galicia's biggest city, forcing the evacuation of a shopping mall and a PSA Peugeot Citroen factory on the outskirts of the city.
The flames had reached O Castro, a large hilltop park in the heart of Vigo with sweeping views of the city's estuary, Spanish public television station TVE reported.
Images broadcast on Spanish TV showed local residents, their mouths and noses covered with handkerchiefs, battling the flames with buckets and pans of water.
People attempt to help out fires in Vigo out by passing buckets of water. Photo: Miguel Riopa/AFP
The city of around 300,000 residents has opened up two sports centres and booked rooms in three hotels for people who were forced to evacuate their homes.
At least 10 schools cancelled classes on Monday in Vigo because of the flames, local officials said.
Spanish state-owned rail operator Renfe said it had cancelled a train linking Vigo to Barcelona because of the wildfires.
Several roads in Galicia were closed because of the flames, local officials said.
The national weather office is forecasting rain and cooler temperatures in Galicia beginning early on Monday which officials hope will help put out the flames.
Meteorologists say Ophelia is the most powerful hurricane recorded so far east in the Atlantic and the first since 1939 to travel so far north.