UN food chief urges crisis action

"We're seeing about 100 million people... who maybe didn't need assistance six months ago but today simply can't afford enough food for their family."

Ms Sheeran said the price of rice in Asia had soared from $460 a ton on 3 March to more than $1,000 seven weeks later. The global prices of wheat, rice and maize have nearly doubled in the past year.

"We can purchase less food than we could in June - in fact, 40% less," she said.