LISBON, Portugal (AP) — Five thousand firefighters struggled Tuesday to contain multiple wildfires raging across northern Portugal that are blamed for causing three deaths and forcing an unknown number of residents to flee their homes. Some 100 fires reported by national authorities stretched the firefighting brigades. Authorities have yet to give figures on how many people have had to evacuate and how many homes have been lost.

Portuguese state broadcaster RTP showed images of houses burnt to the ground and smoke billowing over charred terrain in the area of Castro de Aire. One civilian has died from burns and another from cardiac arrest from the fires that broke out over the weekend, according to civil protection authorities. Among the hardest hit areas is the district of Aveiro, south of the northern city of Porto, where a firefighter died from an unspecified illness while on duty.

Portuguese Prime Minister Luís Montenegro said on Monday that the firefighter was “victim of a sudden illness” and offered his condolences to his family, friends and co-workers. Ground units were supported by Portuguese water dumping aircraft. Fellow European Union members Spain, France Italy and Greece have committed to providing eight more planes to help local forces.

“The EU stands with Portugal as it battles major wildfires,” European Commission President Ursula von der Leyen said in a message on X. “I thank France, Greece, Italy and Spain for their rapid reaction. This is EU s.