The United Nations World Food Programme (WFP) warned on Wednesday that the window to save lives is closing as famine looms in Sudan's war-torn regions, with civilians trapped by intensified fighting in northern Darfur. The threat of famine is growing, especially for 5 million Sudanese already on the brink of starvation. In all, nearly 18 million people are facing acute hunger, while half the population - some 25 million people - are in need of humanitarian assistance.