The global nuclear watchdog's board of governors has formally declared Iran in breach of its non-proliferation obligations for the first time in 20 years.
Nineteen of the 35 countries on the board of the International Atomic Energy Agency (IAEA) voted for the motion, which was backed by the US, UK, France and Germany.
It says Iran's "many failures" to provide the IAEA with full answers about its undeclared nuclear material and activities constitutes non-compliance. It also expresses concern about Iran's stockpile of enriched uranium, which can be used to make reactor fuel but also nuclear weapons.
Iran condemned the resolution as "political" and said it would open a new enrichment facility.
It follows a report from the IAEA last week which criticised Iran's "general lack of co-operation" and said it had enough uranium enriched to 60% purity, near weapons grade, to potentially make nine nuclear bombs.
Iran insists its nuclear activities are entirely peaceful and that it would never seek to develop or acquire nuclear weapons.
Under a landmark 2015 deal with six world powers, Iran agreed to limit its nuclear activities and allow continuous and robust monitoring by the IAEA's inspectors in return for relief from crippling economic sanctions.
Iran also committed to help the IAEA resolve outstanding questions about the declarations under its Nuclear Non-Proliferation Treaty (NPT) Safeguards Agreement.
However, US President Donald Trump abandoned the agreement during his first term in 2018, saying it did too little to stop a pathway to a bomb, and reinstated US sanctions.
Since 2019, Iran has increasingly breached restrictions of the existing nuclear deal in retaliation, particularly those relating to production of enriched uranium.
