The United States has tightened the screws further on Iran with sanctions on its metal industry on the day Tehran said it was suspending some of its commitments under the 2015 nuclear deal with world powers.
The White House said that the new sanctions, announced on May 8, target Iran's steel, aluminum, copper and iron sectors -- all key sources of revenue for the country.
Hours earlier, Iran said that it will no longer sell its surplus enriched uranium and heavy water to other nations as stipulated in the nuclear agreement between Tehran and six world powers. It also threatened to enrich its uranium stockpile closer to weapons-grade levels in 60 days if world powers fail to negotiate new terms.
The moves came on the anniversary of U.S. President Donald Trump's decision to withdraw the United States from the 2015 accord, which aimed at curbing Iran's nuclear program in return for relief from sanctions.
Britain, France, and Germany -- the Western European parties to the nuclear pact -- criticized Iran's "unwelcome" step and warned Iran not to abandon the deal.
Russia, another signatory to the agreement, said Washington was to blame for Iran's decision.
In a statement, Trump said that the new sanctions target "Iran's revenue from the export of industrial metals -- 10 percent of its export economy -- and puts other nations on notice that allowing Iranian steel and other metals into your ports will no longer be tolerated."
Washington has already moved to restrict Iran's oil exports, the country's largest source of hard currency.
"Tehran can expect further actions unless it fundamentally alters its conduct," Trump said, adding that he was open to talks.
"I look forward to some day meeting with the leaders of Iran in order to work out an agreement and, very importantly, taking steps to give Iran the future it deserves," the U.S. president said.
In an address to the nation earlier on May 8, Iranian President Hassan Rohani said that Iran will begin to build up its stockpiles of low-enriched uranium and of heavy water, which is used in nuclear reactors, including a reactor that could produce weapons-grade plutonium.
In 60 days, Iran will increase its enrichment of uranium beyond 3.67 percent, which is permitted by the accord, if the remaining signatories of the 2015 accord -- Britain, France, Germany, Russia, and China -- fail to protect Iran's oil and banking industries from U.S. sanctions.
But the Iranian president also said that his country still supported the nuclear agreement, known as the Joint Comprehensive Plan of Action (JCPOA).
"The Iranian people and the world should know that today is not the end of the JCPOA," Rohani said. "These are actions in line with the JCPOA."
During a visit to London, U.S. Secretary of State Mike Pompeo said that Washington will wait to see if Tehran follows through on its threats before deciding its next move.
World Leaders Respond
Speaking alongside Pompeo, British Foreign Secretary Jeremy Hunt said that Iran's threat to resume higher enrichment of uranium is an "unwelcome step" and he urged Iran "not to take further escalatory steps" and to "stand by its commitments."
German Foreign Minister Heiko Maas expressed "great concern" at Iran's threat and said that "all steps must be avoided that could endanger regional stability and security."
French Defense Minister Florence Parly said that the question of sanctions "will be raised" if the nuclear deal isn't respected, adding that Europeans “absolutely want to keep this agreement alive."
Russian Foreign Minister Sergei Lavrov said that the United States "is to blame for the situation and it makes it difficult for both Iran to fulfill its obligations."
He also accused Western signatories to the deal of trying to "divert attention" from their inability to fulfill their obligations.
China’s Foreign Ministry said that Beijing "resolutely opposes" unilateral U.S. sanctions against Iran and called for strengthened dialogue.
In Washington, the special assistant to the U.S. president and senior director for weapons of mass destruction, Tim Morrison, said Iran’s announcement was "nothing less than nuclear blackmail of Europe."
Tensions between Tehran and Washington have escalated since Trump announced the U.S. pullout, arguing it was flawed because it did not include curbs on Iran’s development of ballistic missiles or Tehran’s support for proxies in the Middle East.
Washington also reinstated sweeping sanctions that have badly hit the Iranian economy.
Despite the U.S. moves, Tehran has continued to comply with the terms of the deal, according to the United Nations' International Atomic Energy Agency.
European backers of the deal have been trying to salvage the agreement, but Tehran has complained that the process was too slow.
The United States has recently said there had been threats to its forces and the country’s allies from Iran.
A U.S. aircraft carrier battle group is heading to the waters near Iran, and Pompeo on May 7 paid an unannounced visit to Baghdad, where he met with Iraqi officials to discuss U.S. security concerns amid what he called “escalating” Iranian activity.