On 6 July Tehran informed the International Atomic Energy Agency that it was enriching uranium to 20% at its research reactor. Uranium metal is used to make a nuclear warhead core. The development immediately prompted Berlin, London and Paris, which are all parties to the 2015 nuclear deal - along with the USA, Russia, and China - to issue a damning joint statement accusing Iran of a ‘grave breach’ of its obligations. ‘Iran has no credible civilian need for uranium metal R&D and production, which are a key step in the development of a nuclear weapon,’ the statement said. According to Iran’s foreign minister, this enrichment is needed for ‘peaceful, medicinal and humanitarian uses.’ The three countries urged Tehran to stop the violations and return to Vienna’s negotiating table where the original signatories to the deal have been working for months to mediate indirect talks between Iran and the USA.