The dangerous heat is the result of a large high-pressure system drawing in warm, dry air over the Continent, and it could last through at least Monday in some places.

ATHENS, Greece — Wildfires intensified across southern Europe on Wednesday with a round-the-clock battle to protect the perimeter of Greece’s third-largest city and at least three deaths reported in Spain, Turkey and Albania.

Red heat alerts have been issued in parts of Italy, France, Spain, Portugal and the Balkans, warning of significant risks to health as temperatures push above 40C (104F). Spain's weather service Aemet said temperatures could reach 44C (111.2F) in Seville and Cordoba, while southern Portugal could also hit 44C.