A U.N. agency says world food prices have reached a new historic peak.

The U.N. Food and Agriculture Organization said its food price index was up 3.4 percent in December from a month earlier.

Rising food prices have been among the triggers for protests in Egypt, Algeria and elsewhere.

FAO says the food price index in January reached 231 points, the highest level registered since 1990 when the agency started monitoring prices. The index regularly checks monthly changes in global food prices, looking at cereals, fats, dairy, sugar and meat prices. Only meat prices were stable.

FAO economist Abdolreza Abbassian said in a release Thursday that the increase in world food prices is not abating.