He further expressed doubt that the European countries would take practical steps to operationalize the INSTEX, while hoping that the mechanism will become operational after joining of Norway, Sweden, Denmark, Finland, Belgium and the Netherlands.
Germany, Britain and France kickstarted the mechanism in January under pressure from Iran that has been demanding trade to stay in the 2015 nuclear agreement known as JCPOA. The mechanism was devised to allow European companies to trade with Iran without falling under sanctions, which the USA has threatened to impose on anyone doing business with designated Iranian entities.
The three European countries are signatories of JCPOA.
After the US pullout, Tehran demanded that the European signees mitigate the damages inflicted on Iran's economy by the renewed USA sanctions and it began exceeding some uranium-enrichment limits set out under the accord.
INSTEX is supposed to be a financial channel and a special mechanism for transferring money in spite of US sanctions on Iran.
Iran and the remaining parties launched talks to save the JCPOA after the U.S. withdrawal, but the three European Union parties to the deal (France, Britain, and Germany) have failed to ensure Iran's economic interests.
The European members have previously missed several deadlines set by Iran to come up with feasible plans, and now it has lifted the ban on the 300 kilograms nuclear fuel stockpile limit in the agreement and started nuclear research activities again.
Most recently Iran's Foreign Minister Javad Zarif chided the European countries publicly in a Tweet shortly before the fresh wave of protests in Iran accusing them of "procrastinating" and claiming that Iran has honored its part of the JCPOA.
It represents "a clear expression of our continuing commitment to the Joint Comprehensive Plan of Action" - the 2015 Iranian nuclear deal - the trio added.
Iran has however taken steps to increase uranium enrichment in its Fordow nuclear facility.
US envoy to Germany Richard Allen Grenell, in a tweet on Saturday night, criticized the six European nations for deciding to join the financial mechanism.
A Former US National Security Council Assistant for the Middle East, Rob Malley, told Reuters in February that INSTEX is "a symbolic political move" that can encourage Iran to remain committed to the JCPOA.