The Catholic bishops of South Sudan have issued an appeal for "immediate and unconditional concrete intervention" as the humanitarian situation in the region grows increasingly desperate.

The bishops warned in a statement that an estimated 4.9 million people will be in food crisis and many close to famine by April. They added: "The figure is expected to rise to 5.5 million people at the height of the lean season in July if nothing is done to curb the severity and spread of the food crisis."

They said: "The food security situation in South Sudan continues to deteriorate since the outbreak of fighting in December 2013, the humanitarian crisis has spiralled with more than three million people fleeing the conflict and seeking refuge in neighbouring countries and others as internally displaced persons hosted across the country.