4.8 million South Sudanese are in urgent need of food, agriculture and nutrition assistance, UN agencies say.
The 4.8 million does not include the figure of over 300 thousand South Sudanese Internally Displaced Persons seeking protection in UN camps, the agencies say.
People are likely to face severe food shortages and the risk of hunger catastrophe over the coming months, warn FAO, UNICEF and WFP.
This is the highest level of hunger since conflict in South Sudan began in December 2013.
It is not the first time the UN agencies are raising the food insecurity alarm this year.