Waiving sanctions on Iran for what he says is the final time, President Donald Trump has warned that unless "terrible flaws" in the 2015 nuclear deal are fixed, the United States will withdraw from it.
Trump has constantly criticized the pact inked between the six world powers, namely China, Russia, Britain, France, the United States and Germany, and Iran in 2015, in which the West promised to relieve sanctions on Tehran in exchange for a halt in Iran's efforts to develop a nuclear weapon.
An Iranian government official on Saturday said that Iran would pursue its ballistic missile program despite US pressure, and slammed US President Donald Trump for his "irrational behavior", calling him the "most hated president in American history". "I'm not sure when the announcement will be made, whether it will be made tonight or whether it will be tomorrow", he said. Mr Trump also wants Iran's ballistic missile programme to be addressed.
Deputy Foreign Minister Sergei Ryabkov said Moscow must unite with Europe and China and undertake "intense work" to keep the existing plan intact, and decried what he said was a USA attempt to strong-arm the situation.
In a background briefing, senior administration officials said this is Trump's "waiver" on Iran. The most prominent among these is Sadeq Larijani, the head of the country's judiciary.
However, time after time, President Trump has (perhaps reluctantly) certified that Iran was cooperating with the deal.
He also wants Congress to alter existing USA laws that oversee how the federal government treats the Iran deal - but there is no sign lawmakers will do so anytime soon, or at all. The White House wants to negotiate instead with its European colleagues on imposing multilateral sanctions should Iran violate terms produced from those proposed transatlantic talks.
European signatories to the deal have pressured the United States to stick to the accord.
The deadlines for a number of these waivers to be renewed will fall over the coming week, and Trump now is obliged to decide whether to maintain sanctions relief.
The German Foreign Ministry said Berlin would consult with European partners on a common way forward after Trump's declarations but that the country would "continue to campaign for the full implementation of the nuclear agreement".
Mr Trump also wants Iran's ballistic missile programme to be addressed."This is a last chance", the USA president said in a statement on Friday.
Europeans say these issues should be kept separate from discussion of the deal, but in a nod to United States concerns, Mogherini stressed they were raised with Zarif on Thursday.