French Supermarkets Faced Repeated Cyberattacks. Officials Reportedly Suspect Iran Was Behind Them.

French officials believe Iranian hackers were behind the cyberattacks targeting the freezers of different supermarkets over the past weeks, according to a new report.

Citing people familiar with the matter, Reuters detailed that, should the responsibility be confirmed, the hacks would be among the most disruptive since the U.S.-Iran war began in February. Other targets include the Los Angeles transit system and water treatment plants in the U.S.

France was not the only country targeted. Eight European nations had to discard food after their refrigeration systems were tampered with. One Swedish supermarket reported that its refrigerator and freezer controls had been set to 50 degrees Celsius, or 122 degrees Fahrenheit, according to The Associated Press. That figure described the setting entered into the controls.

Swedish grocery chain Coop said seven affected stores were operating again by Tuesday after disconnecting their refrigeration systems from the internet. In Belgium, 15 Carrefour stores were affected on Monday, Reuters reported. The French retailer had already dealt with an attack on refrigeration equipment at 80 franchised stores in France about three weeks earlier. French police said the October attacks caused fires and food losses.

The European Union Agency for Cybersecurity called for countries to share information quickly and coordinate their responses, given the number of markets affected.

France also saw attacks against against blood banks, prompting staff to secure equipment and move supplies before they lost any blood products or samples.

The French Blood Establishment, known by its French initials EFS, said the attack reached its sites through an outside refrigeration supplier. The national blood service said it was not directly targeted. Attackers raised the thresholds that govern temperature and defrosting in some cold storage rooms, changing settings on equipment used to preserve products before they are delivered to hospitals and other health care facilities.

The affected rooms held frozen plasma intended for transfusions and for use in manufacturing medicines. They also held samples for the agency's biobanks, which preserve biological material for future use. The agency said its monitoring and alarm systems detected the changes quickly enough for employees to intervene.

Staff regained control of some equipment and took other units out of service. In those cases, they transferred the contents to other storage as a precaution. EFS spokesperson Charley Dubois told Reuters that staff are on duty around the clock because blood can be needed at any time. When alarms sounded, employees moved supplies to refrigerators without a network connection.