The World Bank issued a global hunger warning last night after severe droughts in the US and eastern Europe sent food prices to a record high.

Damage to crop harvests from exceptionally dry weather this year raised sharply the Bank's food price index taking it above its peak in early 2011.

The Washington-based bank blamed the drought in the US for the 25% price rise of maize and 17% price rise in soya beans last month, adding that a dry summer in Russia, the Ukraine and Kazakhstan lay behind the 25% jump in the cost of wheat.

"Food prices rose again sharply threatening the health and well-being of millions of people," said World Bank group president, Jim Yong Kim. "Africa and the Middle East are particularly vulnerable, but so are people in other countries where the prices of grains have gone up abruptly."

The bank said food prices overall rose by 10% between June and July to leave them 6% up on a year earlier. "We cannot allow these historic price hikes to turn into a lifetime of perils as families take their children out of school and eat less nutritious food to compensate for the high prices," said Kim. "Countries must strengthen their targeted programs to ease the pressure on the most vulnerable population, and implement the right policies."

He added that the Bank was spending $9bn this year supporting agriculture and pledged that help to poor countries affected by food price hikes would continue.