The United States said Thursday that "a possible deal" on a new Iranian nuclear accord is close but time is running out and several obstacles have prevented an agreement.
Negotiators meeting in Vienna to try and salvage the 2015 nuclear deal, which is meant to prevent Tehran from acquiring an atomic bomb, have made "significant progress," State Department deputy spokeswoman Jalina Porter told reporters, echoing other nations in recent weeks.
"We are close to a possible deal, but a number of difficult issues still remain unsolved," she said.
"We will not have a deal unless we resolve quickly the remaining issues," she added.
However, "if Iran shows seriousness, we can and should reach an understanding of mutual return to full implementation of the JCPOA within days," she said, using the acronym for the 2015 deal.
Enrique Mora, the European Union's coordinator for the talks, also said they were in the "final stages."
"Some relevant issues are still open, and success is never guaranteed," he Tweeted, adding "we are definitely not there yet."
The so-called Joint Comprehensive Plan of Action, signed in 2015, secured sanctions relief for Iran in return for strict curbs on its nuclear programme.
The agreement was between Iran on one side and Germany, China, the United States, France, Britain, and Russia on the other.
The agreement unravelled when former US president Donald Trump withdrew from it in 2018.
Iran's stockpile of enriched uranium has now reached more than 15 times the limit set out in the 2015 accord, the UN's IAEA nuclear watchdog said Thursday.