BRUSSELS — European Union foreign ministers meeting in Brussels on Monday scrambled to work out how to salvage the Iran nuclear deal despite Tehran’s breaching the agreed limits on its uranium enrichment program and warnings that it might go much further.
Arriving at the meeting, the British foreign secretary, Jeremy Hunt, said there was a little time left to save the Iran deal.
“Iran is still a good year away from developing a nuclear bomb. There is still some closing, but small window to keep the deal alive,” Mr. Hunt said.
The European signatories to the deal, Britain, France and Germany, issued a joint statement Sunday evening that said they were still committed to the deal and regretted that the United States had chosen to reimpose sanctions on Iran “even though that country had implemented its commitments under the agreement.”
“We believe that the time has come to act responsibly and to seek ways to stop the escalation of tension and resume dialogue,” the three countries said in the statement. “The risks are such that it is necessary that all stakeholders take a break, and consider the possible consequences of their actions.”
But the Iranian foreign minister, Mohammad Javad Zarif, said that he saw little reason to be optimistic that the European signatories could save the agreement — known formally as the Joint Comprehensive Plan of Action — by alleviating the punishing effects of American sanctions against Iran.
“The Europeans claim they were willing to maintain the J.C.P.O.A., but we have not seen Europe yet to be ready for an investment,” he said on Sunday after arriving in New York for a meeting of the United Nations, Iran’s state-run Press TV reported.
Iran has sent mixed signals about its intentions in recent days, with President Hassan Rouhani expressing a willingness to open new talks with Washington — once sanctions are removed.
“We are always ready for negotiation,” he said in a televised speech. “The moment you stop sanctions and bullying, we are ready to negotiate.”
But a spokesman for the Atomic Energy Organization of Iran, Behrouz Kamalvandi, said on Monday that unless Europe could salvage the deal, his country would return its nuclear program to its status before the accord, when its uranium stockpile was much larger and some of the element had been much more highly enriched.
Tensions with Tehran have mounted since President Trump last year withdrew the United States from the 2015 accord that scaled back Iran’s nuclear program and reimposed economic sanctions that had been lifted under the deal. The limits set in the deal were intended to prevent Iran from developing a nuclear weapon.
Mr. Trump imposed additional sanctions this year, attempting to cut off Iran’s ability to sell oil, a pillar of its economy.
Britain, France and Germany have made a commitment to ease the impact of American sanctions but so far have not found an effective way to do so.
The centerpiece of their efforts is the creation of a kind of exchange that would allow European companies to do business with Iran in a way that bypasses the American banking system, but Tehran has said that the system, known as Instex, is inadequate.
Arriving at the meeting of Europeans on Monday, Josep Borrell, the Spanish foreign minister and nominee to become the European Union’s foreign affairs chief, said, “We will do what we can to guarantee that there is no economic embargo against Iran and that European companies can continue working there.”
“It’s very difficult because U.S. laws applied in an extraterritorial manner, in a way that we don’t recognize, make it difficult,” he said, adding that Spain would join the Instex mechanism.
Despite the renewed sanctions, Iran complied with its commitments under the nuclear deal for a year after Mr. Trump’s withdrawal. But the confrontation has escalated since the American president imposed further sanctions.
Iran warned that it would stop complying with the deal’s cap on its enriched uranium stockpile unless the Europeans made good on their promises, and then said that it would exceed the pact’s restrictions on how highly enriched the uranium could be. In each case, the European countries were unable to deliver, and Iran surpassed the limits this month.
In May and June, six tankers were damaged near the Strait of Hormuz, the vital waterway that carries much of the world’s oil, and American officials said the ships had been attacked by Iran.
Last month, Iran shot down a United States surveillance drone, which American officials said was over international waters but which Tehran said had violated Iranian airspace. Mr. Trump ordered a military strike in retaliation, but then retracted the order.
This month, British authorities seized an Iranian tanker near Gibraltar that they said was carrying oil to Syria, in violation of European Union sanctions. Days later, London said that one of its naval ships had to chase away three Iranian boats that had been trying to impede a British tanker.
Britain offered on Saturday to return the Iranian ship if the oil were sent somewhere other than Syria.