Addressing the United Against a Nuclear Iran pressure group being held near the annual UN General Assembly, Pompeo said he was "disturbed and indeed deeply disappointed" by Monday's announcement from remaining members of an international nuclear deal.

"This is one of the most counterproductive measures imaginable for regional peace and security," Pompeo said, accusing the European Union of "solidifying Iran's ranking as the number-one state sponsor of terrorism."

"I imagine the corrupt ayatollahs and IGRC were laughing this morning," Pompeo added at the event in New York, referring to the elite Revolutionary Guards, in a speech that was interrupted several times by anti-war protesters.

President Donald Trump pulled out of an agreement negotiated under his predecessor Barack Obama for Iran to curtail its nuclear program sharply in exchange for sanctions relief.

EU foreign policy chief Federica Mogherini, speaking late Monday alongside Iranian Foreign Minister Mohammad Javad Zarif, said that the agreement was in the global interest and pointed to UN inspectors' findings that Iran is in compliance.

She said that European Union members were working on a legal entity that would allow businesses to buy oil and conduct other business with Iran in hopes of avoiding US sanctions.