New delhi  - Global commodity prices were unlikely to ease in the short term owing to a shortage of supply, a top United Nations official said Wednesday, and warned that this could lead to more food riots.

"The rise in prices of food commodities all over the world, is not going to ease in the short term in view of supply-demand situation," Jacques Diouf, director general of the UN's Food and Agriculture Organization (FAO) was reported as saying by PTI news agency.

"The world food situation is very serious today with food riots reported from many countries like Egypt, Cameroon, Haiti, Burkina Faso and Senegal. We fear that this may spread to other countries," Diouf said after talks with Indian Food Minister Sharad Pawar.

The UN official told reporters that the world had 405 million tonnes of cereal stocks that could feed the global population for only eight to 12 weeks.

Diouf said people in the developing countries would be affected the most by rising food prices as they spend 50-60 per cent of their income on food.

Increasing demand in developing countries, particularly in China and India, and diversion of food grains towards production of bio-fuels were partly responsible for rising commodity prices around the world, he said.

Diouf said the FAO had called an emergency meeting of heads of states from June 3-5, 2008, to discuss the overall situation including the impact of climate change on agriculture.