Rising prices for food have led the United Nations programme fighting famine in Africa and other regions to warn that it can no longer afford to feed the 90m people it has helped for each of the past five years on its budget.

The World Food Programme feeds people in countries including Chad, Uganda and Ethiopia, but reaches a fraction of the 850m people it estimates suffers from hunger. It spent about $600m buying food in 2006. So far, the WFP has not cut its reach because of high commodities prices, but now says it could be forced to do so unless donor countries provide extra funds.