The United Nations says world food prices dropped sharply in September, though prices remain generally higher than they were a year ago.

The U.N. Food and Agriculture Organization says its monthly Food Price Index, released Thursday, was down 2 percent from August. It says the drop reflected falling prices for most commodities, with the cost of sugar, grains, and oils decreasing the most.

The FAO says the drop was largely due to increased supplies or improving supply prospects. The weak global economy and the strengthening U.S. dollar played a role as well.

The agency warns certain regions continue to face food insecurity, most notably East Africa.

It estimates that 32 countries are in need of external food aid — most of them in Africa but also several in Asia, including Afghanistan and Pakistan.

The FAO index stands at 225 points, down from the record high of 238 in February but well above its September 2010 mark of 194.