About 13 million people are facing severe food shortages in the Sahel region of West and Central Africa, dpa quoted the international agency Oxfam saying on Friday. The current food crisis could escalate into a "full scale humanitarian emergency," the group warned, as it launched an emergency appeal for 37 million dollars. "Millions of people are on the threshold of a major crisis," said Oxfam's Mamadou Biteye. "All signs point to a drought becoming a catastrophe if nothing is done soon. The world cannot allow this to happen. A concerted aid effort is needed to stop tens of thousands dying due to international complacency," he said. Biteye said that in some severely affected parts of Chad, villagers had been pounding anthills in order to gather grain collected by ants. They told Oxfam they would have to leave their villages within a month if no help arrived. According to the group, families are migrating to densely populated cities in search of food and jobs. Some 33,000 children have dropped out of school as a result. Food prices have spiralled across West Africa in recent years, exacerbating the situation. According to the United Nations Food and Agriculture Organization, agricultural production in the region is down 25 per cent from 2010. Chad's food production is down by as much as 50 percent from last year. The next harvest is not due until October.