WASHINGTON — President Trump said Tuesday the United States will withdraw from the Iran nuclear agreement and re-impose sanctions on Iran, a decision likely to anger allies who fear the prospect of a nuclear arms race in the heart of the Middle East.

“The Iran deal is defective at its core,” Trump said during a speech at the White House.

Trump also announced that Secretary of State Mike Pompeo is again traveling to North Korea to meet with Kim Jong Un in order to set up a meeting with Trump about Kim’s nuclear programs.

Trump denounced the 2015 agreement as “disastrous,” saying it gives Iran too much room to cheat on nuclear weapons development, though in the past he has delayed steps that would effectively render it moot.

Democratic lawmakers and other supporters of the agreement said the decision would alienate allies and encourage Iran to disregard the deal and pursue nuclear weapons.

Trump, meanwhile, spoke by phone with national leaders who support the agreement, including French President Emmanuel Macron.

Hours before an Iran speech at the White House, Trump himself took to Twitter to taunt one of the architects of the deal, former secretary of State John Kerry, for his recent campaign to preserve it.

“John Kerry can’t get over the fact that he had his chance and blew it!” Trump tweeted. “Stay away from negotiations John, you are hurting your country!

In the run-up to Trump’s announcement, a string of European leaders, lawmakers, and arms control officials implored Trump to stay within the agreement.

Killing it, they said, would only trigger nuclear weapons development by the Iranian regime, threatening a nuclear weapons race throughout the ever-volatile Middle East.

Cites Israeli ‘evidence’

In his speech, Trump bashed Iran for what he called support of terrorism and threats toward Israel.

He also cited claims by Israeli Prime Minister Benjamin Netanyahu that Iran has cheated on development of nuclear weapons, though Netanyahu cited documents created before the agreement went into effect.

In a public letter to Trump on Monday, a dozen Senate Democrats said unilateral withdrawal by the United States would create unforeseeable problems.

“Iran could either remain in the agreement and seek to isolate the United States from our closest partners, or resume its nuclear activities,” said the Democratic letter. “Either scenario would be detrimental to our national security interests.”

David Rothkopf, a visiting scholar at the Carnegie Endowment for International Peace, called Trump’s move “a blunder” that “undercuts our standing and credibility, alienates our allies, empowers our enemies and will make the Middle East more dangerous.”

Noting that Trump wants some sort of nuclear deal with North Korea but is killing an exist pact with Iran, Rothkopf said Trump’s main motive appears to be reversing Obama’s policies. He said Trump “has made US foreign policy all about him and as a consequence he has put all the rest of us and America’s leadership role in the world at risk.”

Others, including top Trump aides and congressional Republicans, urged the president to go ahead and terminate. They said sanctions relief has provided Iran the money necessary to build up a ballistic missile program and to finance fighters in rival countries.

“He should not hesitate to nix this flawed and dangerous agreement that is beyond fixing,” said Sen. Marco Rubio, R-Fla.

In Iran, President Hassan Rouhani said his country will maintain engagement with the world regardless of Trump’s decision.

“It is possible that we will face some problems for two or three months, but we will pass through this,” Rouhani said.

Hours before his Iran remarks, Trump spoke with one of the partners in the Iran agreement, Chinese President Xi Jinping. Other topics included U.S. trade disputes with China, as well as another major nuclear project: Trump’s upcoming meeting with nuclear-armed North Korea Kim Jong Un. The phone call came hours after Xi met with Kim.

In previous months, Trump has refused to re-certify the Iran agreement, but has held off on a key move: Re-imposing economic sanctions on the Tehran regime.

Trump has said he wanted to give partners and lawmakers a chance to improve the deal in which the U.S. and allies pulled back sanctions as Iran gave up the mechanical means to make nuclear weapons.

Under the complex agreement signed by the Barack Obama administration and partners in 2015, the United States has granted waivers to a variety of previous sanctions on the regime.

Trump faces a Saturday deadline on a waiver for sanctions on Iran’s central bank, a key part of Tehran’s lucrative oil market. The decision on whether to continue granting this waiver figures to be a key part of Trump’s remarks Tuesday.

There is a July deadline for a waiver on sanctions targeting Iranian businesses and individuals. It is not known whether Trump will address that waiver in his afternoon speech.

Kelsey Davenport, director of nonproliferation policy with the Arms Control Association, said Trump is threatening an agreement “that is verifiably blocking Iran’s pathways to nuclear weapons.” Urging U.S. partners to somehow sustain the agreement, Davenport said breaching it “risks manufacturing a nuclear crisis that the international community cannot afford.”

In earlier reviews of the Iran agreement, Trump’s foreign policy team included officials who basically supported staying in the agreement, but seeking improvements to it.

That group included Secretary of State Rex Tillerson and National Security Adviser H.R. McMaster, but they have left the administration.

Their replacements, Mike Pompeo and John Bolton, have been much more critical of the agreement, one reason that many analyst believe Trump will take steps to void it.

After tweeting Monday to announce his Iran speech, Trump — who has spent much of hos president trying to undo Obama administration programs — attacked Kerry for speaking to foreign officials about somehow keeping the Iran agreement in place.

“The United States does not need John Kerry’s possibly illegal Shadow Diplomacy on the very badly negotiated Iran Deal,” Trump said. “He was the one that created this MESS in the first place!”