Washington's decision practically excludes the head of Iranian diplomacy Mohammad Javad Zarif from any possible future dialog between Washington and Tehran, the Efe news reported.
In a statement to the media, a senior administration official said that Zarif had acted as a "propaganda minister," not as a foreign minister; and US Secretary of State Mike Pompeo accused him of being a "complicit" to Iran's "malign activities" in the Middle East.
"This action represents another step toward denying the Iranian regime the resources to enable terror and oppress the Iranian people," Pompeo said in a statement.
The US Department of Treasury said in a press release that Zarif "oversees a foreign ministry that has coordinated with one of the Iranian regime's most nefarious state entities, the IRGC-Qods Force (IRGC-QF), which is designated pursuant to terrorism and human rights authorities."
Theoretically, these corps report directly to the already previously sanctioned Supreme Leader Ali Khamenei.
With these type of sanctions, Washington seeks to freeze all assets that the individuals may have in the US and prohibits them from making financial transactions with any US citizen, which in theory makes it difficult for them to access the dollar-based international financial system.
However, just after the sanctions were announced, Zarif mocked Washington's punishment on Twitter saying that he has no assets under US jurisdiction, so the sanctions don't affect him.
"The US' reason for designating me is that I am Iran's 'primary spokesperson around the world. Is the truth really painful?" he asked.
"It has no effect on me or my family, as I have no property or interests outside of Iran. Thank you for considering me such a huge threat to your agenda," he added.
When the US takes such measures it also forbids the subjects to travel to its territory. However, as head of Iranian diplomacy, Zarif frequently visits the United Nations headquarters in New York.
Asked whether the sanctions will prevent Zarif from going to the UN, an official assured that the State Department would "comply" with the 1947 agreement between the UN and the US, whereby US authorities pledge to allow officials travelling to the international organisation to enter the country.
( With inputs from IANS )