Zarif specially took Sweden to task, urging the country to allow the sale of wound dressings for Iranian kids suffering from a painful skin condition known as EB.
Sweden, along with Belgium, Denmark, Finland, the Netherlands and Norway, announced last week to be joining INSTEX, which is designed to circumvent U.S. sanctions against trade with Iran by avoiding use of the dollar.
 European powers – Germany, France and Britain - have been tinkering with the much-hyped special trade vehicle for months, but they have failed to have up and running even to handle food and medical trade.  
"Instead of arrogant threats or hollow paper promises, E3/EU—and future INSTEX shareholder Sweden—should start with something very simple; a minimal human duty: Ask Mölnlycke Health Care to SELL products enabling Iranian kids with EB to cover their wounds,” Zarif tweeted Monday.
"Economic Terrorism kills,” Zarif added in his tweet, referring to the U.S. economic sanctions on Iran. "Pompeo once again admits that US Economic Terrorism on Iran is designed to starve, and in the case of medical supplies, kill our innocent citizens,” he added.
In an interview with BBC Persian in November, U.S. Secretary of State Mike Pompeo brazenly said Iranian officials must listen to Washington "if they want their people to eat".
Washington claims the sanctions target the government, but ordinary Iranians are the ones who suffer the most.
The trade of humanitarian goods, such as food, medicine and medical devices, is theoretically allowed by the U.S., but European companies refuse to do business with Iran out of deference to the Americans.
Since the reimposition of sanctions, Swedish medical products firm Molnlycke Health Care has stopped delivering Mepilex dressings which are trusted around the world to treat a wide range of chronic and acute wounds, including in EB patients, Iranian media reports say.
Hamidreza Hashemi-Golpayegani, the head of the NGO that helps such patients, said last month that at least 15 Iranian children with epidermolysis bullosa (EB) have died since the U.S. launched its new sanctions on Iran in August.
Often known as butterfly children because their skin is as fragile as the wings of a butterfly, EB patients need special care. Even mild frictions or bumps cause severe blistering of the skin which is very painful.
They often have difficulty with their daily activities, such as walking, eating and even breathing, but without proper protective bandages, their agony would be heartbreaking.