WASHINGTON: US President Donald Trump says he is extending sanctions relief for Iran one last time so Europe and the US can fix the nuclear deal's "terrible flaws".
The waiver he will sign suspends US sanctions on Iran for another 120 days.
The White House wants EU signatories to agree permanent restrictions on Iran's uranium enrichment. Under the current deal they are set to expire in 2025.
Iran's Foreign Minister Mohammad Javad Zarif said it was a "desperate attempt" to undermine a "solid" deal.
Germany said it would continue to call for the deal's full implementation and would consult on a "common way forward" with the UK and France. Mr Trump also wants Iran's ballistic missile programme to be addressed.
"This is a last chance," the US president said in a statement on Friday. "In the absence of such an agreement, the United States will not again waive sanctions in order to stay in the Iran nuclear deal.
"And if at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately."
Also on Friday, the US imposed separate sanctions against 14 Iranian individuals and entities it accuses of rights abuses, censorship and support for weapons proliferators.
The US still maintains sanctions on Iran - independent of the nuclear deal - on matters such as terrorism, human rights and ballistic missile development.