President Donald Trump has confirmed the withdrawal of the US from the Iran nuclear accord, saying the arrangement was "defective at its core". 

Mr Trump said that if he allowed the deal to stand, there would soon be a nuclear arms race, and called Iran a "regime of great terror".

Despite lobbying from European allies,the US President moved forward with his campaign promise to pull out of the Obama-era agreement.

He signed a presidential memorandum withdrawing saying he is planning to reinstall sanctions on the Iranian regime.

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France, Britain and Germany released a joint statement saying they regret the US president's decision to withdraw from the deal.

Former US president Barack Obama has called the move a "serious mistake," and warned it will erode America's global credibility.

The deal with Iran was struck in 2015 with the US, UK, Russia, China, France and Germany.

Under the Joint Comprehensive Plan of Action (JCPOA), Tehran agreed to significantly cut its stores of centrifuges, enriched uranium and heavy-water, all key components for nuclear weapons.

The country agreed to the deal as a way of circumventing billions in economic overseas sanctions from the United Nations, United States and the European Union.

Iran's president Hassan Rouhani warned the country would start enriching uranium in the coming weeks, if talks with allies remaining in the deal failed. 

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Speaking in an address to the nation, Mr Trump said that he will be reinstating the "highest level" of sanctions and warned other countries not to help the Iranian government.

He said despite his previous warnings, the "disastrous" deal must be reformed and the necessary changes had not been secured.

He said: "The United States no longer makes empty threats. When I make promises, I keep them."

Mr Trump said the JCPOA was a "great embarrassment" to him and warned it would lead to an "arms race" in the Middle East.

He said: "The Iran deal is defective at its core. If we do nothing, we know exactly what will happen.

"In just a short period of time, the world's leading state sponsor of terror will be on the cusp of acquiring the world's most dangerous weapon.

"Therefore, I am announcing today that the United States will withdraw from the Iran nuclear deal."

The president said any nation that "helps Iran in its quest for nuclear weapons" could also be strongly sanctioned by the US.

"America will not be held hostage to nuclear blackmail," he said.
Israeli Prime Minister Benjamin Netanyahu praised Mr Trump's decision as a "historic move", saying the accord was a "recipe for disaster".

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Mr Netanyahu is a leading critic of the deal, saying it did not contain sufficient safeguards to prevent Iran from reaching nuclear-weapons capability or address Iran's other activities across the region.

Mr Trump said if Iran "continues its nuclear aspirations it will have bigger problems than it has ever had before".

He added: "I want to deliver a message to the long-suffering people of Iran: The people of America stand with you."

In a joint statement, Prime Minister Theresa May, German Chancellor Angela Merkel and French President Emmanuel Macron said Mr Trump's decision was a matter of "regret and concern" and that they remained committed to the deal.

They said: "It is with regret and concern that we, the leaders of France, Germany and the United Kingdom take note of President Trump's decision to withdraw the United States of America from the Joint Comprehensive Plan of Action.

"Together, we emphasise our continuing commitment to the JCPoA. This agreement remains important for our shared security.

"We recall that the JCPoA was unanimously endorsed by the UN Security Council in resolution 2231.

"This resolution remains the binding international legal framework for the resolution of the dispute about the Iranian nuclear programme.
"We urge all sides to remain committed to its full implementation and to act in a spirit of responsibility."

The three leaders said they would work to find a "positive" way forward.
Mr Rouhani spoke live on Iranian state television saying he would send Foreign Minister Mohammad Javad Zarif to countries remaining in the accord.

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He said: "I have ordered Iran's atomic organisation that whenever it is needed, we will start enriching uranium more than before."

He said Iran would start this "in the next weeks".

Meanwhile, Shadow foreign secretary Emily Thornberry said that Boris Johnson's previous visit to Washington had shown up Britain's lack of influence with the US administration. 

Ms Thornberry said that while France's President Emmanuel Macron and German chancellor Angela Merkel had held face-to-face talks with Donald Trump, Mr Johnson's intervention was restricted to an appearance on Fox News.

"I think that is a by-product of a long and unnecessary indulgence of Donald Trump that has been happening for too long by this Government," she told the BBC Radio 4 Today programme," she said. 

"I think that if you allow the new president to believe that that sort of behaviour is normal then I think that your influence later is less."