Firefighters battled massive blazes tearing through forests across France and Spain Monday, as authorities warned of a fresh heatwave set to engulf the scorched French wine-growing region around the major city of Bordeaux. More than 325,000 people have fled their homes, mostly in the Gironde department, home to Bordeaux, as some of the worst forest fires in either country's history rage across southwest France and central Spain near Madrid. France's fire has caused an unprecedented "pyrocumulonimbus" – a giant fire cloud that creates its own winds and packs lightning that causes more blazes, said the National Firefighters Federation of France (FNSPF). "It's a David-versus-Goliath scenario... at some point, we'll find a weak spot and strike there," said FNSPF spokesman Eric Brocardi. French President Emmanuel Macron will hold a crisis cabinet meeting to discuss the emergency on Monday morning.

Smoke from the fires 70 kilometres (44 miles) west of Madrid can be smelt in the Spanish capital © Oscar Del Pozo, AFP

Spanish Prime Minister Pedro Sanchez will visit fire-hit areas in Valencia, in the east of the country on Monday where firefighters are battling a new blaze and where 15,000 people have been forced to flee their homes. On Sunday, during a visit to the fire zone in Avila province west of Madrid, he warned: "Difficult hours lie ahead." Spain's Interior Minister Fernando Grande-Marlaska said Sunday evening the fires were advancing, but slowly. Earlier Sunday, civil protection chief Virginia Barcones, describing the fire around Avila, said the country was battling a "monster". "We are dealing with a perimeter of 280 kilometres encompassing 77,000 hectares (190,000 acres)," Barcones told state broadcaster TVE of the wildfire. 'Extremely intense' Scientists say climate change is making such extreme weather events more frequent and intense. Coming at the height of the summer holiday season, the fires were fuelled by woodland parched to tinder by successive heatwaves and lack of rain since May. In France, the prefect of the southwestern Gironde region and where the country's fires are concentrated, urged tourists to stay away and seek "other destinations".