EU cybersecurity chief Juhan Lepassaar warned on Tuesday that home appliances could be the next hacking target after attacks on supermarket fridges across Europe.

Supermarkets in at least 12 European countries were hit by cyberattacks in October and November, with France the worst affected. The attacks also disrupted refrigeration systems at French blood banks.

"Today it was fridges, tomorrow it could be routers, the day after tomorrow it could be home appliances," said Lepassaar, executive director of ENISA, the EU's cybersecurity agency. "Security should not and cannot be an afterthought."

France blamed Iran's Revolutionary Guards for the attacks on its supermarkets. The Pentagon is investigating freezer failures at U.S. military base grocery stores as a suspected hack.

Lepassaar urged Europe to invest more, saying incidents could be avoided. "Cybersecurity is not cheap," he said. An ENISA report warns that artificial intelligence is shrinking exploitation time to near zero.

Lepassaar said threats should be anticipated when connected products are designed. "Every service has digital elements that can be hacked," he said. He warned attacks could block hospitals, police and fire services.

He said state-linked groups from China, Iran and North Korea target Europe, European companies and interests. An April Financial Times report said Chinese cyberintelligence uses smart refrigerators to attack institutions. Britain's National Cyber Security Centre said Chinese intelligence uses tens of thousands of home devices to build botnets.

In Poland, Digitalization Minister Krzysztof Gawkowski said 140 large refrigerators were identified as vulnerable. U.S. federal agencies have called on hospitals, transport companies and food retailers to strengthen industrial refrigeration systems.