The United Nations is at risk of 'imminent financial collapse' due to member states not paying their fees, the body’s head has warned.

António Guterres said the UN faced a financial crisis which was 'deepening, threatening programme delivery', and that money could run out by July.

He wrote in a letter to ambassadors that all 193 member states had to honour their mandatory payments or fundamentally overhaul the organisation's financial rules to avoid collapse.

This warning comes after the UN's largest contributor, the US, refused to contribute to its regular and peacekeeping budgets, withdrawing from several agencies it deemed a 'waste of taxpayer dollars.'

Guterres stated that the UN had faced financial crises in the past but that the current situation was 'categorically different.'

He specified that decisions not to honor assessed contributions financing a significant share of the approved regular budget have been formally announced, without naming the specific member states involved.

Guterres emphasized that the 'integrity of the entire system' depends on states adhering to their legal obligations under the UN charter to pay their 'assessed contributions', noting that unpaid fees had reached a record 77% of the total owed by the end of 2025.

He also pointed out that a regulation requiring the UN to return unspent money created a 'double blow', expecting to give back cash that doesn't exist.

Guterres remarked: 'I cannot overstate the urgency of the situation we now face. We cannot execute budgets with uncollected funds, nor return funds we never received.'

He concluded, 'The bottom line is clear: either all member states honour their obligations to pay in full and on time – or member states must fundamentally overhaul our financial rules to prevent an imminent financial collapse.'