Iran rejected on Tuesday a White House accusation that Tehran was long violating the terms of its nuclear deal with world powers, after the Islamic Republic said it had amassed more low-enriched uranium than permitted under the accord.
"Seriously?" Foreign Minister Mohammad Javad Zarif said in a message on social network Twitter, after a statement by White House press secretary Stephanie Grisham that said, "There is little doubt that even before the deal's existence, Iran was violating its terms."
Tehran's announcement drew a warning from President Donald Trump that Tehran was "playing with fire."
The move marked Iran's first major step beyond the terms of the pact since the United States pulled out of it more than a year ago.
However, Zarif said the move was not a violation of the accord, arguing that Tehran was exercising its right to respond to the U.S. walkout.
The step, however, could have far-reaching consequences for diplomacy at a time when European countries are trying to pull the United States and Iran back from confrontation. It comes less than two weeks after Trump said he ordered air strikes on Iran, only to cancel them minutes before impact.
Iran's semi-official Fars news agency reported that the country's enriched uranium stockpile has now passed the 300-kg (661 lb.) limit allowed under the deal.
The U.N. nuclear watchdog, the International Atomic Energy Agency (IAEA), which monitors Iran's nuclear program under the deal, confirmed in Vienna that Tehran had breached the limit.
Trump, asked if he had a message for Iran, said, "No message to Iran. They know what they're doing. They know what they're playing with, and I think they're playing with fire. So, no message to Iran whatsoever."
European powers, which remain party to the accord and have tried to keep it in place, urged Iran not to take further steps that would violate it. But they held off on declaring the agreement void or announcing sanctions of their own.
The White House charge that Iran probably was in violation of the nuclear deal before and after it was reached in 2015 sharply contrasts with CIA Director Gina Haspel's testimony in January to the Senate Intelligence Committee saying, "At the moment, technically, they are in compliance."
Daryl Kimball, the executive director of the Arms Control Association, said the White House charge was "illogical".
He pointed out that at the time the nuclear deal was concluded, Tehran and the IAEA agreed on a "roadmap" through which Iran is addressing the nuclear watchdog's unanswered questions about the nuclear weapons research program that the IAEA and the U.S. intelligence community assessed ended in 2003.
"The process is still underway," he said.
He also said there was no international standard prohibiting Iran from enriching uranium, as asserted by Pompeo. "That is not the case. That is an American position," he said.
The six U.N. Security Council resolutions that Pompeo asserted established that standard was superseded by Resolution 2231 enshrining the nuclear deal and allowing Iran to enrich uranium within the agreement's restrictions.
While Iran announced on Monday that it breached the deal's restriction on storing more than 300 kg (661 lb.) of low-enriched uranium, Kimball said the issue would be adjudicated through the accord's dispute resolution mechanism.
It was the United States, he said, that first violated the deal when Trump withdrew from it while Iran still was in compliance and then re-imposed harsh U.S. sanctions that had been suspended by the nuclear agreement.
Iran's breach, he said, does not affect the deal's central target of extending to a year the time in which Iran could "breakout" and produce enough highly enriched uranium for a warhead.
The breach is a political move aimed at pressuring the European Union, China and Russia to compensate Iran for the serious damage to its economy from U.S. sanctions, he said.