By David E. Sanger, Edward Wong, Steven Erlanger and Eric Schmitt
WASHINGTON — Iran’s president declared on Wednesday that he would begin to walk away from the restrictions of a 2015 nuclear deal, and the Trump administration responded with a new round of sanctions against Tehran, reviving a crisis that had been contained for the past four years.
The escalation of threats caught the United States’ allies in Europe in the crossfire between Washington and Tehran. And while the announcement by President Hassan Rouhani of Iran did not terminate the landmark nuclear accord that was negotiated by world powers, it put it on life support.
Britain, France and Germany all opposed President Trump’s move a year ago to withdraw the United States from the accord that limited Iran’s capacity to produce nuclear fuel for 15 years. Ever since, the Trump administration has ramped up a pressure campaign against Iran’s military and clerical leaders, including blocking global oil exports and expediting warships and B-52 bombers to the Persian Gulf this week to face down what officials described, without evidence, as a new threat by Tehran against American troops in the Middle East.
European officials had promised to set up a bartering system to evade American sanctions imposed against Iranian oil. But that effort has largely failed, even as Iran complied with its obligations under the agreement, from production limits to inspections.
On Wednesday morning in Tehran, Mr. Rouhani declared he had run out of patience.
“The path we have chosen today is not the path of war, it is the path of diplomacy,” he said in a nationally broadcast speech. “But diplomacy with a new language and a new logic.”
Rather than exit the deal entirely, Mr. Rouhani announced a series of small steps to resume the production of nuclear centrifuges and to begin accumulating nuclear material.
Mr. Rouhani also set a series of carefully calibrated deadlines for European leaders — essentially forcing them to either join the United States in isolating Iran or uphold the nuclear deal that world powers spent years negotiating with Tehran.
He said the Europeans had 60 days to assure that Iran could “reap our benefits” under the nuclear accord, by making up for lost oil revenues and allowing the country back into the international financial system.
If the Europeans agree, they will be subject to sanctions by the United States. If they dismiss Mr. Rouhani’s claims, he says Iran will take more dramatic steps.
Hours later, the White House announced that it was taking additional measures to squeeze Iran’s economy by imposing sanctions on its steel, aluminum, iron and copper sectors. Iran’s industrial metals industries account for about 10 percent of its exports, according to a Trump administration estimate.
Mr. Trump said in a statement that the move “puts other nations on notice that allowing Iranian steel and other metals into your ports will no longer be tolerated.”
Under John R. Bolton, the national security adviser who has long advocated pressing for regime change in Iran, the White House has been urging ever-escalating sanctions.
“Iran has a choice,” Tim Morrison, the National Security Council’s arms control director, said at a conference organized by the Foundation for Defense of Democracies, a Washington-based think tank. “At some point, even the mullahs will get it.”
At the State Department, officials said the United States was willing to reopen nuclear negotiations with Iran, as long as the talks were broadened to include possible limits on missile launches and the country’s support of armed militias and terrorist groups. Mr. Rouhani and his diplomats have made clear that the United States must first return to the 2015 deal before entering any new negotiations.
In London, Secretary of State Mike Pompeo, who has been among the most vocal of the Iran hawks in the Trump administration, initially played down the Iranian announcement as “intentionally ambiguous.”
Later, however, he issued a blistering statement that denounced Iran’s action as “in defiance of international norms and a blatant attempt to hold the world hostage.”
Iran’s “threat to renew nuclear work that could shorten the time to develop a nuclear weapon underscores the continuing challenge the Iranian regime poses to peace and security worldwide,” Mr. Pompeo said.
None of the actions that Mr. Rouhani warned of would get Iran to a nuclear weapon anytime soon. But they would resume a slow, steady march that the 2015 agreement temporarily stopped.
Jeremy Hunt, the British foreign secretary, agreed that Iran must be prevented from developing a way to build a nuclear weapon.
He added, however, that “it’s no secret we have a different approach on how best to achieve that.” Britain is still adhering to the nuclear deal.
The nuclear accord with Iran was brokered under the Obama administration, in partnership with Britain, France, Germany, China and Russia. It limited Tehran’s nuclear program in exchange for easing international economic penalties that had crippled Iran’s economy. Mr. Trump’s withdrawal from the deal, along with the restarting of the sanctions, has put huge domestic pressure on Mr. Rouhani to strike back at the United States.
European officials have been the most critical of Mr. Trump’s approach, arguing that as long as the Iranians were remaining faithful to their commitments — as international inspectors attested — there was no basis for reimposing sanctions. They have also pointed to Iran’s compliance in shipping 97 percent of its nuclear fuel out of the country as helpful in curbing Tehran’s nuclear ambitions.
In turn, European officials have said, Western nations have had more leverage with Iran when discussing other security concerns, including its ballistic missile program.
“Today nothing would be worse than Iran, itself, leaving this agreement,” Florence Parly, the French defense minister, said on the BFM TV news channel.