Spain on Thursday mourned its third wildfire death this week and Greece began beating back a blaze threatening its third-largest city as an unrelenting heat wave stoked tinderbox conditions in southern Europe.

The European Union is sending two planes to help Spain tackle raging wildfires, after the country activated an EU disaster assistance mechanism for the first time. Spanish Interior Minister Fernando Grande-Marlaska told local media he had requested two water bomber aircraft from the EU to be deployed to the worst-affected areas.

A volunteer firefighter died from severe burns and several people were hospitalised as the state weather agency warned that almost all of the country was at extreme or very high risk of fire.