Almost 50 million Americans - one in seven - are struggling to get enough to eat, according to a US federal survey on "food insecurity".

Because of the credit crisis, up to 15 percent of all households, equal to 49.1 million people, have difficulty "obtaining food for all their members due to a lack of resources".

The report released by the US Department of Agriculture (USDA) shows a 3.5 percent increase in people without sufficient means to buy food in 2008 compared to 2007, when 11.1 percent were classified as "food insecure". The latest figures represent the highest level observed since nationally representative food security surveys were initiated in 1995.

President Barack Obama called the USDA report "unsettling", especially as there were children involved, and vowed to reverse the trend of rising hunger.

Some 60 heads of state and government are currently attending the UN food security summit in Rome.