The UN’s top human rights official has issued an urgent warning that an imminent offensive against El Obeid, the capital of Sudan’s North Kordofan state, carries the risk of serious international crimes and threatens to deepen an already catastrophic humanitarian crisis.

The head of the UN-affiliated atomic energy agency on Thursday welcomed the signing of an initial Iran-US memorandum aimed at ending the war, before proposing “to sit down” with both parties to assist with concrete measures such as verification of Iran’s nuclear programme, a key sticking point.

Millions of people already facing hunger, displacement and economic hardship could soon face another major climate shock, as UN agencies warned on Thursday that extreme weather risks are intensifying across some of the world’s most vulnerable regions.