"Thank you for considering me such a huge threat to your agenda," Zarif tweeted following an announcement by the U.S. administration on Wednesday that the designation of Zarif as the "primary spokesperson" of Iran's Supreme Leader Ayatollah Ali Khamenei, whom the U.S. administration sanctioned in late June.
"Zarif implements the reckless agenda of Iran's supreme leader," the announcement added.
"The U.S. reason for designating me is that I am Iran's primary spokesperson around the world. Is the truth really that painful?" Zarif noted.
U.S. designation "has no effect on me or my family, as I have no property or interests outside Iran," he added.
On Thursday, Iran's Foreign Ministry Spokesman Abbas Mousavi also said that "the Americans are seriously scared from the logic of Zarif and his art of negotiations."