PARIS, France: A major cyberattack on supermarket refrigeration systems in France caused fridge temperatures to rise to 50 degrees Celsius overnight, sparking fires and spoiling large amounts of food across hundreds of stores.

The disruption was not limited to France. Dutch supermarket operator Ahold Delhaize said it was dealing with a security problem in its network and had taken several systems offline as a precaution.

The Paris prosecutor's office said the attack affected connected refrigerators at several major food retailers. Reported damage included food losses and fires.

Prime Minister Sébastien Lecornu ordered France's National Cybersecurity Agency (ANSSI) to investigate the incident, a source in his office said. Authorities were also checking whether the attack could affect other French businesses and whether companies in other European countries were at risk.

Les Mousquetaires, the group that owns Intermarché, said around 150 of its stores had been affected. Refrigerators in those outlets were heated to 50 degrees Celsius for about six hours.

The company said it had discarded all the affected food to avoid health risks.

Dominique Schelcher, chief executive of supermarket group Coopérative U, also confirmed that his business had been hit.

"Targeting equipment essential to the preservation of fresh products and to the food supply of the French people is of extreme gravity and is unprecedented," he wrote on X.

Carrefour said 80 of its supermarkets were affected, although most of its 6,000 stores continued to operate without problems.

Other major French supermarket chains, including Monoprix, E.Leclerc and Auchan, did not respond to requests for comment.

Dutch Retailer Reports Security Problems

The company operates Albert Heijn, the Netherlands' largest supermarket chain, and has significant operations in the United States.

Albert Heijn's smartphone app informed customers that grocery deliveries were unavailable because of a cybersecurity incident. Online orders account for around 10 percent of the retailer's sales.

Its physical stores remained open. Dutch news agency ANP reported that rival supermarkets had received an increase in delivery orders as customers looked for alternatives.

It was not clear whether the problems affecting Ahold Delhaize were connected to the attack on French supermarkets.

Ahold Delhaize is also the fourth-largest grocery retailer in the United States. Websites for its Stop & Shop, Giant, Hannaford and Food Lion chains displayed notices saying their sites were temporarily down.

The extent of the disruption to its other operations was not immediately known.

Outdated Refrigeration Software Under Probe

A source close to Lecornu said ANSSI had identified a vulnerability in refrigeration management software supplied by Danish company Danfoss.

Danfoss confirmed that it was aware of incidents in France involving a limited number of refrigeration management systems.

The company said the affected units were using outdated firmware, the software that controls the equipment.

Danfoss added that it had repeatedly advised customers to keep supported systems updated with the latest firmware and to replace older systems with current-generation alternatives.

Investigators are examining the incident and its wider impact. The full extent of the damage, who was responsible, and any possible connection to the problems reported in the Netherlands and the United States remained unclear.