The World Food Programme (WFP) has said there "very well could be" famine in remote areas of Yemen where the UN's food agency does not have access.
"Yemen is a disaster and I don't see any light at the end of the tunnel right now," WFP's Executive Director David Beasley told reporters on Thursday.
The WFP has warned that Yemen is on the brink of a full-blown famine, with 18 million of its 29 million population food insecure, 8.4 million severely so, Al Jazeera reported.
The country's civil war further worsened in the wake of Saudi-led military intervention in 2015, which has ravaged the country's economy and caused the Yemeni riyal to collapse, depreciating 180 percent.
The cost of food has increased by 35 percent in the last 12 months and if trends continue the riyal will reach an exchange rate of 1,000 to the US dollar, putting 12 million at risk of starvation, UN officials have warned.
"Yemen is undeniably the world's worst humanitarian crisis by far," said Beasley.
Yemen is in the grip of a humanitarian disaster with millions facing starvation and disease after years of war on the country.
The Saudi-led war in Yemen started in 2015 as an attempt to crush Houthi Ansarollah movement in the region and reinstall former president Abd Rabbuh Mansur Hadi. The conflict has created a dire humanitarian situation in the country.