Major French supermarket chains on Monday said they were hit by a cyberattack that caused their refrigerators to shoot up in temperature in hundreds of stores, forcing spoiled food to be thrown away and raising concerns about food security.

Top retailers E. Leclerc, Intermarche and Cooperative U confirmed to AFP they suffered a cyberattack that Cooperative U's chief executive described as "unprecedented".

"Food security requires more attention at all levels," said the EU's food and agriculture commissioner Christophe Hansen on X, condemning the attack and saying such "exploitation of food" was now a "reality".

At least 300 shops of Intermarche or its Netto brand were targeted, along with over 100 Cooperative U outlets, and several E. Leclerc stores, the retailers told AFP in separate statements.