A cyberattack targeting three cold-storage sites of France's national blood service attempted to raise refrigeration temperatures to extremely high levels but was detected before any blood products or samples were damaged, authorities said.

The French Blood Establishment (EFS) said temperature and defrosting thresholds were raised to extremely high levels on Monday at three of its plasma storage facilities.

However, monitoring and alarm systems quickly detected the unusual changes, allowing staff to take immediate action to protect the stored products.

"No health consequences have been identified, and no blood products were lost," the EFS said in a statement issued late Tuesday.

The attack targeted a supplier of refrigeration equipment used at the three facilities.

The stored products included plasma bags intended for transfusions and plasma used in the manufacture of medicines. They were either transferred to other facilities or secured, the statement said.

The EFS said blood collection and distribution operations had continued without interruption, ensuring that hospitals and other healthcare facilities could maintain services for patients.

France's national cybersecurity agency and the Health Ministry are investigating the incident.

The attack comes amid reports of similar cyber incidents affecting supermarkets in several European countries this week, where remotely accessed refrigeration systems caused fridges and freezers to warm up, resulting in millions of euros worth of spoiled food.