President Donald Trump’s long-expected announcement today that he would disavow the Iran nuclear deal was immediately condemned by European leaders, who view the accord as essential for averting another conflict in the Middle East at a time when the world is worried about tensions on the Korean Peninsula.

In an unusual joint statement, Prime Minister Theresa May of Britain, Chancellor Angela Merkel of Germany and President Emmanuel Macron of France said that they “stand committed” to the 2015 deal and that preserving it was “in our shared national security interest.”

“The nuclear deal was the culmination of 13 years of diplomacy and was a major step towards ensuring that Iran’s nuclear program is not diverted for military purposes,” they said after Trump spoke, noting that the U.N. Security Council had unanimously endorsed the deal and that the International Atomic Energy Agency had confirmed Iran’s compliance with it.

“We encourage the U.S. administration and Congress to consider the implications to the security of the U.S. and its allies before taking any steps that might undermine” the nuclear agreement, including reimposing sanctions on Iran, the leaders added.

But Saudi Arabia and Israel, which are both adversaries of Iran, welcomed Trump’s announcement that he would no longer certify the nuclear deal with Iran.

Trump’s decision does not terminate the agreement with Iran. Instead, it leaves it to Congress to decide whether to impose new sanctions on Iran — a step that would effectively trash the deal.

Benjamin Netanyahu, the Israeli prime minister who has always opposed the agreement with Iran, said that Trump’s announcement created “an opportunity to fix this bad deal” and was a sign of Trump’s determination to “boldly confront Iran’s terrorist regime.”

Saudi Arabia, which has waged a proxy battle against Iran for supremacy in the region and was the first country Trump visited after taking office, said it welcomed what it called a “new U.S. strategy” toward Iran.

In his remarks today, Trump warned that unless the nuclear agreement with Iran could be changed and made permanent — to prevent Iran from ever developing nuclear weapons — then he would terminate the deal.

Trump did not give a deadline. But under the current arrangement, Trump said, “Iran can sprint” toward the development of nuclear weapons when the deal’s restrictions expire.

Some of the prohibitions in the agreement are set to end in 2025, including limits on the number of its centrifuges. Iran, which has always maintained that its nuclear program is for peaceful purposes, not for weapons, would not agree to a permanent freeze in its ability to enrich nuclear fuel.

That must be changed, Trump said, or he would scrap the deal altogether.

Iran has long resisted the idea of renegotiating the nuclear agreement in the West’s favor. Last month, its foreign minister rejected extending the length or conditions of the accord, saying that Iran would only consider changing the agreement if the concessions it has already made — including giving up nuclear fuel — were reconsidered.

The foreign minister, Mohammad Javad Zarif, said that would mean Iran would retake possession of the stockpile of nuclear fuel it shipped to Russia when the accord took effect.

“Are you prepared to return to us 10 tons of enriched uranium?” Zarif said of the relinquished stockpile — one of Iran’s biggest concessions.

Iran has accused the United States of violating the letter and spirit of the deal by imposing additional sanctions against it, and its mission on Friday warned that Iran might itself back away from the deal.

“Iran has many options on how to proceed and if necessary will terminate its commitment regarding this issue,” the statement said, without elaborating.

European leaders expressed deep concern about Trump’s decision. Like Russia and China, they have long warned the United States not to back away from the agreement.

Before Trump’s announcement, President Vladimir Putin of Russia voiced alarm at the prospect of Trump’s undermining the deal, which Iran negotiated with Britain, China, France, Germany, Russia and the United States.

Putin’s spokesman, Dmitry Peskov, told reporters Friday that a U.S. withdrawal from the deal “undoubtedly will affect the atmosphere of predictability, security, stability and nonproliferation in the world,” according to Tass, the Russian news agency.

The Russian foreign minister, Sergey Lavrov, called his Iranian counterpart, Zarif, to reiterate Russia’s commitment to the deal, the news agency said.

In Germany, officials have repeatedly shown support for the accord in recent days, and have warned that a U.S. decision to walk away from it could damage the relationship between the United States and Europe. Steffen Seibert, a German government spokesman, told reporters in Berlin on Friday that his country viewed the deal as “an important instrument to prevent a nuclear-armed Iran.”

“That’s why we will continue to work towards its full implementation,” he said. “If an important country like the United States comes to a different conclusion, as appears to be the case, we will work even harder with other partners to maintain this cohesion.”

British officials had pressed the Trump administration to respect the deal. May called Trump to emphasize that it was “vitally important for regional security.”

Boris Johnson, the British foreign secretary, also tried to make that point to his U.S. counterpart, Secretary of State Rex Tillerson, saying the deal was “making the world a safer place,” The Daily Telegraph reported.

Agnès Romatet-Espagne, a spokeswoman for the French Foreign Ministry, said Friday that it viewed the deal as “an instrument at once strong, robust and verifiable, that guarantees that Iran will not develop a nuclear weapon.”

“We wish to see it fully implemented by all parties involved,” she told reporters at a news conference. “Multilateralism is the only way to solve international problems that respects all parties involved, by way of dialogue and exchange.”

Under the terms of the deal, Iran agreed to accept severe limits on its ability to enrich uranium fuel for 15 years, in exchange for the revocation or suspension of economic sanctions, including a European oil embargo.

The deal also imposed for the first time a verification mechanism that allowed the international community to make sure that Iran was abiding by its promises not to pursue nuclear weapons.

It was a major diplomatic triumph for the Obama administration, and it has been praised by arms control groups who say it helped avert a potential conflict or nuclear arms race in the Middle East.

There are fears that the basic framework of the accord could collapse if the United States walks away. Peskov, the Kremlin spokesman, told reporters today that Russia believed Iran would abandon the deal if the United States did.

And as tensions between the United States and a nuclear-armed North Korea have escalated in recent months, European leaders have seen the Iran deal as an important example of a possible diplomatic way forward.

Germany’s foreign minister, Sigmar Gabriel, highlighted the implications of the deal for North Korea in an interview Thursday with German newspaper group RND. He warned that a U.S. withdrawal could set off a scramble for nuclear weapons, threatening both international security and the European-American relationship.

“Some states could understand the breakdown of the Iran deal as a signal to provide themselves with nuclear weapons as quickly as possible,” he said. “Then we would not only have North Korea as an acute problem.”

© 2017 The New York Times Company