The pressures in global food markets have grown so intense that, for the first time in its history, the World Food Programme is finding it hard to procure supplies of essential commodities, senior officials at the United Nations body indicated on Friday.

In particular, they said, countries in the emerging world are now placing so many export controls on items such as wheat in order to conserve them for their own populations that they have sometimes refused to release supplies when the WFP has asked for emergency goods.