The nuclear challenge at the heart of Trump's Iran negotiations

Here is the latest breaking news from around the world: The nuclear challenge at the heart of Trump's Iran negotiations2 hours ago Share Save Add as preferred on GoogleTom EdgingtonBBC VerifyGetty ImagesThe US is confident that a deal to end the war with Iran will be signed in the next few days, a senior Trump administration official has said. The agreement could reopen the Strait of Hormuz in return for the US lifting its blockade on Iranian shipping. While officials say the deal will also lead to the destruction and removal of Iran's enriched uranium stockpiles - a key component of nuclear weapons - the technical details are still being worked out.

If and when an agreement is signed, it will likely be judged against the 2015 nuclear agreement negotiated by the Obama administration and other nations, which was abandoned by Trump during his first term. Trump's 'nuclear dust' plansUranium is a naturally occurring radioactive element. It contains special properties that can be used to fuel nuclear power plants, but also help develop nuclear weapons.

The Details

However, it needs to be "enriched" first, a process that involves increasing the concentration of uranium-235 isotope - the essential component of nuclear fuel. Since the war started on 28 February, Trump has repeatedly said Iran needs to surrender its stockpiles. "They're going to give us the nuclear dust", he said on 29 March.

He reiterated this in an interview with NBC on 7 June, saying: "If we make a deal now we're friendly, we'll all go together. It'll be our equipment. We'll take it out and destroy it, whether it's onsite or whether we take it offsite.

"Iran, however, has previously said "zero enrichment" is a red line and a violation of its rights. Getty ImagesTrump has said Iran needs to hand over its "nuclear dust"The fate of Iran's uranium stockpile was central to the 2015 nuclear agreement - the Joint Comprehensive Plan of Action (JCPOA) - which imposed strict limits on Iran's enrichment activities. "The number one issue that was running at that time was whether Iran was going to go for building a nuclear weapon", former JCPOA lead negotiator Baroness Ashton told Verify.

What Experts Say

When it was introduced, the Obama administration declared that the JCPOA would prevent Iran from building a secret nuclear programme and that Tehran had agreed to "extraordinary and robust monitoring, verification, and inspection". In exchange, the US agreed to lift sanctions against Iran, including on oil, trade and banking. Under the deal, Iran could only keep a small amount of monitored, low-enriched uranium.

It had to reduce its stockpile by 98% (to 300kg; 660lbs), could enrich only up to 3. 67% purity and limits were placed on its centrifuges - the machines used to enrich uranium. Low-enriched uranium - typically 3-5% purity - is enough to produce reactor fuel required for a nuclear power station, but weapons-grade uranium needs to be at least 90% enriched.

The development has drawn wide international attention, with diplomatic circles watching closely.