The European Union has vowed to intensify efforts to save the 2015 Iran nuclear deal, after Tehran took another step towards being able to develop an atom bomb.
Brussels noted “with deep concern” Iran’s decision to begin enriching uranium to levels not seen since the 2015 pact with world powers, the bloc’s foreign affairs spokesman Peter Stano said.
He said the move at the underground Fordo facility "will have serious implications when it comes to nuclear non-proliferation".
"We will redouble our efforts to preserve the agreement and return to its full implementation by all parties," Mr Stano said.
Iran breached the limits set out by the agreement – officially known as the Joint Comprehensive Plan of Action – in 2019 after US President Donald Trump withdrew the US from the deal the year before and enacted heavy sanctions on Tehran.
The other parties to the accord, such as the EU, UK, France and Germany have been desperately trying to keep it alive.
Last week, Iran informed the UN’s nuclear watchdog that it intended to begin enriching uranium to 20 per cent purity – higher than the 3.67 per cent limit allowed under the pact, but significantly lower than the 90 per cent required for an atom bomb.
The development came after troops from Iran's Islamic Revolutionary Guard Corps seized a South Korean vessel on Monday in the Arabian Gulf.
“It is vital that freedom of navigation is maintained and that trade is able to safely pass through international waters in this region, including the Strait of Hormuz, one of the world’s busiest and most important waterways,” said a spokesperson from the UK’s Foreign, Commonwealth and Development Office.
Tensions between Tehran and Seoul have heightened in recent months over Iranian funds frozen in South Korean banks because of US sanctions.
Iran has increased pressure on South Korea to unlock around $7 billion, which it says was earned before the US widened sanctions on Tehran's oil exports.