A cyberattack disrupted refrigerator monitoring and control systems at three regional blood banks in France overnight between Sunday and Monday, prompting staff to transfer blood supplies to unaffected storage units.

"Several regional facilities of the French Blood Establishment (EFS) were affected by a cybersecurity incident that impacted certain cold storage room monitoring and control systems," the health ministry said in a statement.

However, the attack did not affect blood supplies, EFS spokesperson Charley Dubois said.

"We have staff round the clock since blood can be needed at any time. They were warned about the problems by alerts and moved the blood to other refrigerators that were not connected," she said.

The attack occurred around the same time hackers tampered with refrigerators at stores in eight European countries, forcing retailers to discard large quantities of food. The incident echoed a similar attack on dozens of supermarkets in France three weeks earlier.

The situation was under control on Wednesday, the health ministry said, adding that remote access to the affected refrigerators had been disabled.

Investigations are under way to determine how the attack was carried out, what equipment may have been affected and when the systems can safely return to service.

Last month, hackers reportedly seized control of cooling units at hundreds of supermarkets in France, causing fires and food losses, police said.

The incidents have raised concerns across the European Union over vulnerabilities in connected infrastructure amid heightened security tensions since Russia's invasion of Ukraine in 2022.