ROME — One in six people in the world — or more than 1 billion — is now hungry, a historic high due largely to the global economic crisis and stubbornly high food prices, a U.N. agency said.

Compared with last year, there are 100 million more people who are hungry, meaning they receive fewer than 1,800 calories a day, the Food and Agriculture Organization said in a report.

Almost all the world's undernourished live in developing countries, where food prices have fallen more slowly than in the richer nations, the report said. Poor countries need more aid and agricultural investment to cope, it said.

"The silent hunger crisis, affecting one-sixth of all of humanity, poses a serious risk for world peace and security," said the agency's Director-General Jacques Diouf.

Soaring prices for staples, such as rice, triggered riots in the developing world last year.

Hunger increased despite strong 2009 cereal production, and a mild retreat in food prices from the highs of mid-2008. However, average prices at the end of last year were still 24 percent higher in real terms than in 2006, FAO said.