BORMES-LES-MIMOSAS, France — Backed by planes dropping water and fire retardant, more than 1,000 firefighters battled wildfires Wednesday that billowed smoke into the sky over France’s southern Cote d’Azur coast and forced the evacuation of at least 12,000 people.

France’s prime minister, visiting the area, predicted a grim day ahead.

Large swaths of Mediterranean forest have been left bare and blackened after three days of fires. About 250 trailer homes, a hangar, an atelier and several vehicles were burned in the blazes, but no one has been injured so far, the prefect of the Var region said.

Residents and tourists were evacuated early Wednesday after a ferocious fire whipped by strong Mistral winds spread from La Londe-Les-Maures to dense forests around the picturesque hilltop town of Bormes-Les-Mimosas. About 60 people were evacuated by boat from nearby Cap Benat.

“There will be more fires tomorrow,” Prime Minister Edouard Philippe said. He traveled to Bormes on Wednesday night, flew over the devastated region and met with firefighting personnel.

Firefighting aircraft made more than 500 drops of water or retardant on Wednesday, Phillipe said, and only three fires remained active in the Var region — out of dozens that started Wednesday.

But “the situation remains difficult, I must say it. Like me, you feel the wind is blowing,” the prime minister said.

Further south of the French mainland, flames ate through 4,950 acres of forest on the northern end of the French Mediterranean island of Corsica, in what was the largest blaze in France.

Fires also were blazing across parts of bone-dry Portugal and Italy.

Tourist Francoise Roparse, who was visiting the south of France, was among the evacuees awakened in the middle of the night who found shelter in a sailing club near Bormes.

“First, it was…