The UN warned on Wednesday that 20 of its operations in Yemen could face further reductions or closure due to lack of funding during the next two months.
Nearly 80 per cent of Yemen's population is reliant on aid after five years of war that has divided the country between the internationally recognised government in the south and the Iran-backed Houthi rebels in the north.
Recurring outbreaks of cholera and the rampant spread of the coronavirus have added to the humanitarian crisis.
Twelve of the UN’s 38 major programmes have already been closed or drastically reduced, the UN said in a statement.
“We have no choice,” Lise Grande, the UN's Humanitarian Co-ordinator for Yemen said.
“We have a moral obligation to warn the world that millions of Yemenis will suffer and could die because we don’t have the funding we need to keep going.”
The impact of under-funding is dramatic, the organisation said.
In April, food rations for more than 8 million people in northern Yemen were halved and humanitarian agencies were forced to stop reproductive health services in 140 facilities.
International donors promised $1.35 billion for Yemen at a conference on June 2, short of the UN target of $2.4bn that it says is needed to avoid severe cuts to the world’s biggest aid operation.
But Yemen remains the world’s worst humanitarian crisis.