The United States says Iran's plan to breach the limit on its stockpile of enriched uranium, which was set under a 2015 nuclear deal with world powers, amounts to "nuclear blackmail" and must be met with "increased international pressure."
White House National Security Council spokesman Garrett Marquis made the comments on June 17 after Iran followed through on its threats to further scale back its compliance with the agreement that curbed Iran's nuclear program in exchange for relief from crippling economic sanctions.
President Hassan Rohani called for urgency in rescuing the accord, which has been on the brink of collapse since the United States backed out of it last year.
The Western European signatories to the pact -- France, Britain, and Germany -- insisted that Tehran stick to its commitments under the deal. Paris urged Iran to be "patient and responsible," while London said it would “look at all options” if Tehran fails to abide to the agreement.
In May, Iran stopped complying with some commitments in response to President Donald Trump's decision to withdraw the United States from the deal.
Trump has also reimposed sanctions against Tehran that had been eased under the agreement aimed at heading off any pathway to developing a nuclear bomb.
Tehran, which has said its nuclear program was strictly for civilian energy purposes, has complained that European powers have failed to abide by their commitments to mitigate the effects of the U.S. sanctions on its economy.
A spokesman for the Iranian Atomic Energy Organization said on state television on June 17 that the country had quadrupled production of enriched uranium, which is used to make reactor fuel and potentially nuclear weapons, and will exceed the limit on its stockpile set out in the nuclear agreement within the next 10 days.
The accord limits Iran's stock of low-enriched uranium at 300 kilograms of uranium hexafluoride enriched to 3.67 percent, or its equivalent, for 15 years.
"Iran's reserves are every day increasing at a more rapid rate. And if it is important for [the Europeans] to safeguard the accord, they should make their best efforts," said the Iranian spokesman, Behrouz Kamalvandi.”
“As soon as they carry out their commitments, things will naturally go back to their original state," Kamalvandi added.
Speaking later at a meeting with the new French ambassador to Tehran, President Hassan Rohani said France and the other parties to the deal "still have a very limited opportunity to play their historic role for saving the deal," according to a statement on his website.
"There's no doubt that the collapse of the [accord] will not be beneficial for Iran, France, the region, and the world," Rohani added.
In Washington, Marquis said that Iran's uranium enrichment plans “are only possible because the horrible nuclear deal left the their capabilities intact."
Trump "has made it clear that he will never allow Iran to develop nuclear weapons," the White House National Security Council spokesman said, adding: "The regime's nuclear blackmail must be met with increased international pressure."
The U.S. president wants to force Iran to renegotiate the accord, arguing that the terms were not tough enough to prevent Iran from developing nuclear weapons, and agree to curb its ballistic missile program and end its "malign" activities in the Middle East.
U.S. State Department spokeswoman Morgan Ortagus said Iran's announcement "doesn't surprise anybody" and said the international community "should not yield to nuclear extortion."
Macron Urges Patience
Speaking at a news conference in Paris, French President Emmanuel Macron said he "regrets" Iran's announcement, adding that France "strongly encourages Iran to maintain a patient and responsible attitude."
Macron reiterated that he favors maintaining the nuclear deal but wants new talks to encompass Iran's ballistic missile activities.
A spokesman for U.K. Prime Minister Theresa May said her government had been "clear about our concern at Iranian plans to reduce compliance" with the nuclear agreement.
"Should Iran cease meeting its nuclear commitments, we would then look at all options available to us," the spokesman said.
German Foreign Minister Heiko Maas said that it is "incumbent upon Iran to remain committed to its responsibilities."
"Iran cannot just tell the other parties to the deal they must do more, and itself do less than is in this accord," Maas said in Luxembourg.
He also said that "a lot is being threatened, by the way from both sides, and I don't see that as very constructive."
The EU's foreign policy chief, Federica Mogherini, said the bloc will wait for the next report from the International Atomic Energy Agency on Iran's compliance with the international accord before announcing its response.
Meanwhile, Israeli Prime Minister Benjamin Netanyahu, who was a staunch opponent of the nuclear pact, called for international sanctions to be reimposed immediately "should Iran deliver on its current threats."
"In any event, Israel will not allow Iran to get nuclear weaponry," Netanyahu warned.
Tensions between the two countries have risen in recent weeks after the United States accused Iran of involvement in attacks on oil tankers in the Persian Gulf.
In a show of strength, Washington has sent additional forces to the region.
Iran has denied being behind the attacks.