European and world leaders reacted with worry after Iran announced on Monday that it had accumulated more enriched uranium that permitted under its nuclear deal.
"Iran is playing with fire", US president Donald Trump said on Monday night.
The White House said that the U.S. policy of maximum pressure on Iran will continue until it changes course and added that Iran should be held to a standard of no uranium enrichment.
"Maximum pressure on the Iranian regime will continue until its leaders alter their course of action," the White House said. "We must restore the longstanding nonproliferation standard of no enrichment for Iran."
"We want to preserve that deal because we don’t want Iran to have nuclear weapons but if Iran breaks that deal then we are out of it as well," British foreign minister Jeremy Hunt said.
Hunt is one of two contenders to replace Theresa May as prime minister. He told Sky News that Britain still supported the deal.
Israeli Prime Minister Benjamin Netanyahu said that Iran's move to break limits on its stockpile of low-enriched uranium was a "significant step toward making a nuclear weapon".
Last year, Netanyahu presented what he said was a secret Iranian nuclear archive proving that Tehran had lied about pursuing nuclear arms. Speaking in Jerusalem, he said more evidence showing that Iran "lied the entire time" would be exposed soon.
Netanyahu also called upon European countries to "stand by your commitments" to impose sanctions against Iran if it violated the nuclear agreement reached with world powers in 2015. "I tell you: Do so, go do it. Do it. Just do it," he said.
A UN spokesperson said UN chief Antonio Guterres is concerned by reports that Iran had surpassed the limits on its low enriched uranium stockpile set in the nuclear agreement reached in 2015 known as the JCPOA adding that such actions “would not help preserve the Plan nor secure the tangible economic benefit for the Iranian people.”
Iran said its accumulation of more enriched uranium than permitted under its nuclear deal with world powers was not a violation of the pact, since it was exercising its right to respond to the U.S. withdrawal from the agreement last year.
"We have NOT violated the #JCPOA," Foreign Minister Mohammad Javad Zarif wrote on Twitter, referring to the nuclear deal by its formal title, the Joint Comprehensive Plan of Action (JCPOA). "Para 36 of the accord illustrates why. We triggered & exhausted para 36 after US withdrawal. We gave E3+2 a few weeks while reserving our right. We finally took action after 60 weeks. As soon as E3 abide by their obligations, we'll reverse."
Zarif tweeted the message along with the text of paragraph 36 of the JCPOA which provides a mechanism to resolve disputes when parties believe other signatories are not fulfilling their obligations. The E3 refers to Germany, Britain and France, while the E3+2 also includes Russia and China.