France is blaming Iran for last month’s supermarket refrigerator cyberattack, which spoiled produce at around 700 retailers, and is vowing to slap sanctions on Tehran in response.

“This was an attack of unprecedented scale and unprecedented aggressiveness,” Foreign Minister Jean-Noël Barrot told reporters Monday. He described it as the first large-scale cyberattack carried out for sabotage purposes on French national territory.

“It represents a major assault on the nation’s interests and on the security of the French people,” Barrot said. France has summoned Iran’s ambassador and intends to impose retaliatory sanctions “at a European level,” he added.

There was no immediate comment from Tehran on the French allegations.

The cyberattack in October occurred when hackers remotely connected to supermarket refrigerators and freezers, then raised their temperature by switching on defrost cycles, according to CNN affiliate BFMTV. That led to the loss of large quantities of fresh and frozen produce and even caused some of the refrigeration equipment to catch fire.

The Paris prosecutor’s office took up the case and on Monday accused Iran of being behind the attack, citing “the use of Farsi and IP addresses pointing to devices located in Iran.”

The prosecutor’s office said it has opened an investigation into the head of Shahid Kaveh, a cyber unit affiliated with the Islamic Revolutionary Guard Corps, as well as his two deputies and any other individuals responsible.

A similar cyberattack targeted supermarkets in Sweden, Belgium and Ireland earlier this month, though it remains unclear if the incidents are linked to the one in France. No one has claimed responsibility for this month’s cyberattacks in other European countries.

Shortly after the US and Israel launched strikes against Iran in late February, the US intelligence community issued a flurry of private warnings to American companies and government agencies urging vigilance amid the threat of possible cyberattacks from Iran, according to national security sources and memos reviewed by CNN. (CNN)