Iran’s president Hassan Rouhani has announced that the Islamic republic is to inject gas into its centrifuges, a significant step away from the nuclear deal agreed with world powers and in defiance of European calls for restraint.

Last year, US president Donald Trump withdrew the US from the nuclear deal and since May Iran has started rolling back its commitments to the 2015 accord in protest at what it calls the failure of the European signatories to help an economy crippled by US sanctions.

While previous moves were more focused on research and development, western diplomats in Tehran fear the injection of gas into the centrifuges, which had previously spun empty, is an escalation by the authorities in the Islamic republic that further threatens the ailing nuclear deal.