President Trump withdraws from Iran nuclear deal, saying "America will not be held hostage to nuclear blackmail"

US President Donald Trump has announced that the United States is effectively withdrawing from the Iran nuclear deal, defying last-ditch diplomatic efforts by his European allies to convince him otherwise.  

"I made clear that if the deal could not be fixed, the United States would no longer be a party to the agreement. The Iran deal is defective at its core. If we do nothing, we will know what exactly will happen. Therefore, I am announcing today, that the United States will withdraw from the Iran nuclear deal," Trump said in a highly-anticipated address moments ago.

Under the deal signed in Vienna with six world powers - the US, UK, France, Germany, Russia, China and the European Union - Iran scaled back its uranium enrichment programme and promised not to pursue nuclear weapons.  

In exchange, international sanctions were lifted, allowing it to sell its oil and gas worldwide. However, secondary US sanctions remain. The International Atomic Energy Agency (IAEA) has repeatedly confirmed that Tehran has been meeting its nuclear commitments fully.  

A White House statement issued after Trump's speech said the US president directed his "administration to immediately begin the process of re-imposing sanctions" related to the deal, formally known as the Joint Comprehensive Plan of Action (JCPOA).