Iran told the International Atomic Energy Agency (IAEA) that it plans to start enriching uranium up to 20 percent purity, the level it achieved before signing the Joint Comprehensive Plan of Action (JCPOA) in 2015, the Russian ambassador to the agency said.
Mikhail Ulyanov took to Twitter to explain how this information became known.
Last month, Iran passed a bill to increase its uranium enrichment and stop the UN inspecting its nuclear sites in response to the killing of nuclear physicist Mohsen Fakhrizadeh.
In 2015, Iran signed the JCPOA with China, France, Germany, Russia, the UK, the US, and the EU. It required Tehran to curtail its nuclear programme and downgrade its uranium reserves in exchange for sanctions relief. The deal also envisaged lifting the arms embargo five years after the adoption of the JCPOA.
In 2018, the US unilaterally withdrew from the deal and reimposed its sanctions against Iran. Tehran responded by pledging to gradually backtrack on its commitments and resume uranium enrichment unless other JCPOA signatories failed to help it bypass US sanctions.