The crisis in Darfur could become "infinitely worse" if a key deal reached this week to send a mixed United Nations and African force to the war-torn region is not applied quickly, the UN chief of humanitarian affairs said Saturday. "This is the moment of truth for Darfur," UN Undersecretary General for Humanitarian Affairs Jan Egeland told reporters in the Sudanese capital. "We are playing with a powder keg, it could get infinitely worse." More than 200,000 people have been killed and 2.5 million displaced by three years of fighting in the vast, arid Darfur region of western Sudan. An ill-equipped African Union mission has achieved little in preventing the violence from worsening.