Sweden’s Coop chain told the daily Aftonbladet on Monday that six of ​its stores ‌had been ​affected, while ICA said it was “aware that a limited ​number of stores were affected by an incident overnight which impacted their refrigeration and freezer systems”.

The problems follow a case last month in which attackers remotely took control of refrigeration systems in hundreds of supermarkets across France, sending temperatures soaring.