A United Nations agency says global food prices fell slightly in May but will remain “stubbornly” high for the rest of the year and into 2012.

The Food and Agriculture Organization released a price index Tuesday that shows food prices dropped 1 percent in May compared with April — but remain 37 percent above what they were in May 2010.

The U.N. agency says lower cereal and sugar prices led to the slight decrease in the May index, offsetting record high meat and dairy prices. But it says high and volatile food prices are expected through 2012, citing a decline in food stockpiles and only modest production increases for most crops.

The FAO says prospects for wheat harvests in Russia and Ukraine are encouraging, but maize and wheat yields in Europe and North America are potentially in danger because of poor weather.

FAO officials say the high world prices pose a threat to many low-income food deficit countries.

The U.N. food agency says Russia's decision to lift its grain export ban in July could push prices down and help meet increasing demand.

Rising food prices helped spark protests earlier this year in Tunisia and Egypt, prompting unrest across North Africa and the Middle East, which are major grain-importing regions.

Oxfam International last week called for an overhaul of the world's food system, saying prices for staples such as corn will double in the next two decades unless action is taken.