WASHINGTON President Donald Trump announced on Tuesday the United States will withdraw from the Iran nuclear deal .

The U.S. will not extend waivers on sanctions targeting Irans nuclear program, effectively ending its compliance with the 2015 international agreement under which Iran accepted restrictions on its nuclear program in exchange for economic relief.

I am announcing today that the U.S. will withdraw from the Iran nuclear deal, Trump said at the White House. We will be instituting the highest level of economic sanctions.

Trump accused the deal officially called the Joint Comprehensive Plan of Action (JCPOA) of being poorly negotiated and lacking enforcement mechanisms. He said it allows Iran to develop a nuclear weapon in a short time, but offered no evidence to back these assertions. Trump also cited Israeli Prime Minister Benjamin Netanyahus April 30 presentation on Irans nuclear program, which alleged that Iran lied about its past nuclear activities before negotiating the nuclear deal.

At the heart of the Iran deal was a giant fiction: that a murderous regime desired only a peaceful nuclear energy program. Today, we have definitive proof that this Iranian promise was a lie, Trump said.

Nuclear experts and European officials criticized Netanyahus speech for pandering to Trump and offering essentially no new information on Irans nuclear activities. Much of Netanyahus presentation centered on information that was publicly available in a 2007 declassified intelligence report , and Netanyahu did not state that Iran was in current violation of the deal.

European officials, who pushed for Trump to uphold the deal, condemned the presidents decision to pull out. French President Emmanuel Macron tweeted shortly after Trumps speech that France, Germany and the United Kingdom regret the U.S. decision and that we will work collectively on a broader framework. The European Unions top diplomat Federica Mogherini said that the deal was working and fulfilling its promise.

Former President Barack Obama , who touted the Iran deal as one of his chief foreign policy accomplishments, put out a statement criticizing Trumps decision to undo the agreement.

Walking away from the JCPOA turns our back on Americas closest allies, and an agreement that our countrys leading diplomats, scientists, and intelligence professionals negotiated, Obama said.

It is not immediately clear what will happen next. The 2015 nuclear agreement was negotiated among Iran, the U.S. and five other countries the U.K, France, Germany, China and Russia which urged the U.S. not to withdraw. Last month, Iranian Foreign Minister Javad Zarif suggested that if the U.S. pulled out of the nuclear accord, his country could also exit the deal and resume its nuclear program at a much greater speed. Iran has no reason to continue to abide by the agreement if the economic benefits start to diminish, he said.

But most of the economic benefits Iran receives through the nuclear deal do not come directly from the U.S., which maintains a primary embargo against Iran. When Trump previously waived sanctions, he suspended secondary sanctions, which penalize other countries for doing business with Iran.

If you take away U.S. sanctions relief, you are taking away probably the most powerful incentive the Iranians had to do their part, said Richard Nephew, a former State Department official who worked on Iran sanctions policy.

When Trump threatened to pull out of the nuclear agreement last year, the European Unions ambassador to the U.S., David OSullivan, warned that the EU could invoke a blocking statute that would protect European businesses from U.S. secondary sanctions. Theoretically, this means that Iran could continue receiving economic benefits under the 2015 deal and would be compelled to maintain the restrictions on its nuclear program.

But implementing this blocking mechanism or other steps to preserve the deal would be technically difficult and diplomatically risky for European countries.

Its going to be a herculean task, said Reza Marashi, a National Iranian American Council analyst and former State Department official who just returned from two weeks of meeting with officials and experts in Europe.

The real meat on the bones would take at least a year to implement, and they have no plan for anything ... theyve spent most of their energy trying to figure out a way for Trump to stay in.