Nuclear talks between Iran and the US have reached an impasse over Iran’s right to produce and stockpile low-enriched uranium. America first signalled that it was open to some enrichment before insisting that Iran must relinquish that right.

As I prepared to take a photograph of an anti-American mural outside of the former U.S. Embassy in Iran’s capital recently, a passerby called out to me.

By Francois Murphy and John Irish VIENNA (Reuters) -U.N. inspectors monitoring Iran's Fordow nuclear site confronted a major gap in their knowledge last year as they watched trucks carrying advanced uranium-enriching centrifuges roll into the facility dug into a mountain south of Tehran.

A senior Iranian official told CNN the new nuclear deal proposal presented to Tehran in recent days is “incoherent and disjointed,” as sources familiar with the progress of the talks said the momentum behind negotiations to secure a new deal appears to be collapsing.

Iran has dramatically increased its stockpile of uranium needed to create nuclear weapons and has fallen short of compliance with international regulators, according to an IAEA report.