United Nations Secretary General Antonio Guterres has warned that 20 million people in four countries face famine unless the international community steps in to prevent it. <br/><br/>He said, the situation is dire and millions of people are barely surviving in the space between malnutrition and death. <br/><br/>Gutters said, they are also vulnerable to diseases and outbreaks, forced to kill their animals for food, and eat the grain they saved for next year's seeds. <br/><br/>He said UN needs 4.4 billion dollars to prevent catastrophic hunger and famine in South Sudan, Nigeria, Somalia and Yemen. <br/><br/>The United Nations has declared South Sudan, Somalia, Yemen and the northeastern part of Nigeria on the brink of famine in the next six months.