The U.S. on Wednesday sanctioned Iranian Foreign Minister Javad Zarif for working on behalf of Supreme Leader Ayatollah Ali Khamenei, who President Donald Trump blacklisted in June.
The latest action marks an extremely rare designation of a top diplomat and is Trump's first under the order sanctioning Khamenei.
A senior administration official who briefed reporters on condition she not be named said that while the U.S. "historically has placed a high priority on preserving space for diplomacy, there are limits to our patience when a regime so routinely flouts" diplomatic protocols.
Another official who spoke under similar ground rules said the State Department would "evaluate specific circumstances related to this designation on a case-by-case basis," including U.S. obligations to ensure foreign representatives have access to the UN's New York headquarters.
Trump "has placed no restrictions on elected officials having conversations with foreign counterparts," the first official separately added in an apparent sign that foreign officials are unlikely to have their interactions with Zarif affected.
Treasury Secretary Steven Mnuchin first announced the same day in late June that Zarif would be sanctioned that week, but the deadline came and went without action until Wednesday.
"Javad Zarif implements the reckless agenda of Iran’s Supreme Leader and is the regime’s primary spokesperson around the world," Mnuchin said in a statement announcing the blacklisting. "The United States is sending a clear message to the Iranian regime that its recent behavior is completely unacceptable."
The Treasury said "additional information" suggests the Iranian Foreign Ministry under Zarif coordinates with the external operations arm of Iran's Islamic Revolutionary Guard Corps, including efforts to influence elections and facilitate the release of two of the corps' officers held abroad through bribery.
It did not specify which cases it was referencing in making the allegations.
Any property held by Zarif subject to U.S. jurisdiction has been frozen and U.S. persons are now generally prohibited from doing business with the top diplomat.
Zarif quickly responded to the U.S. announcement on Twitter, brushing off any concerns of the action by saying it "has no effect on me or my family, as I have no property or interests outside of Iran".
"Is the truth really that painful?" he asked, apparently rhetorically. "Thank you for considering me such a huge threat to your agenda."
Foreign financial institutions that carry out "a significant transaction" on behalf of Zarif may expose themselves to follow-on sanctions, according to the Treasury.
-'US fears Zarif's negotiating skills'
Iranian Foreign Ministry spokesman Abbas Mousavi accused the U.S. of being "inconsistent" about Zarif.
"The peak of stupidity and inconsistency of American leaders is at a point where they don't see Zarif as an authority in Iranian politics, but with the ultimate ignorance they sanction him," Mousavi said on Twitter.
Mousavi also claimed that the U.S. has “a strong fear of Dr. Zarif's wisdom and his negotiating skills".
By Michael Hernandez in Washington