Greek supermarkets were forced to withdraw several food and beverage products from their shelves this week, after a group threatened to contaminate them with acid as part of an environmentally influenced protest of Christmas consumerism. Authorities urged residents in Athens and the city of Thessaloniki not to buy or consume certain types of Coca-Cola, a Greek milk brand and packages of meat.

Thessaloniki and Athens combined have about 1 million residents who were affected by the precautionary measures. The “Blackgreen Arsonists” — whose name suggests an eco-anarchist outlook — threatened to inject the products with hydrochloric acid, a powerful, colorless corrosive used in research and industry. They said it was because the thousands of people doing their Christmas shopping meant “the sacrifice of millions of living creatures, slaughtered and drained to the last drop to satisfy consumers’ needs.”

To protest this need every year for people to fill their empty lives with “consumer garbage with beautiful and glittering wrappings,” the sabotaged products would be placed on supermarket shelves in the run-up to Christmas.

Authorities said they have no information on the identities of the group members.

Similar threats have emerged in the past and nothing has happened, though in this case the group included photos of its members injecting something into the products as part of their online threat.

Last Christmas, several multinational companies in Greece, including Coca-Cola, Nestlé and Unilever, also had to withdraw some of their products from the shelves following a similar threat, this time by the “Green Nemesis” group, which was categorized as anarchist and “anti-establishment” by authorities at the time. It made its first such threat three years earlier.

Domestic left-wing or anarchist terrorism has a long history in Greece and is more prevalent there than almost anywhere else in Europe. “Italy, Greece and Spain were the only E.U. member states to experience left-wing and anarchist terrorist attacks,” the European Union's law enforcement agency Europol wrote in an assessment of incidents in 2016.

The majority of anarchist groups target governments or state institutions, but about half of their attacks are directed either against businesses or private individuals.

There is no reason to believe that such far-left threats have any connection with radical Islamist terrorism, but the Islamic State group recently urged its supporters living in Western countries to launch poison attacks on supermarkets.

The Islamic State, known as ISIS, and other groups are now urging their supporters to rely on methods less likely to raise suspicions than traditional materials such as explosives, since authorities now monitor shopping sites for unusual sales of chemicals.

In its propaganda material disseminated online, ISIS suggests resorting to knife or vehicle attacks, instead. Documents released by ISIS have also included poisoning as a possible low-key attack strategy, however, and some of the material describes in detail how to produce or purchase lethal substances.

So far, there has been no known ISIS poisoning attack targeting Western grocery stores, but terrorism analysts are concerned by the easy accessibility of some of the substances that could be used in future attacks. Last year, an ISIS sympathizer was charged in the San Francisco Bay area over foiled plans to distribute poisoned drugs in nightclubs.

Unlike the Greek poisoning threat, which has alerted authorities in Europe, the ISIS-inspired plot in the United States did not include a warning — and so likely was a great deal more serious.

Read more: