World food prices fell slightly for the second consecutive month in May but wheat prices rose again as Russia's war in Ukraine rages on and India banned exports of the commodity, a UN agency said Friday.

Russia's invasion of Ukraine sent food prices to a record high in March as both countries are major exports of agricultural goods, sparking fears of a global hunger crisis.

The United Nations Food and Agriculture Organisation's food price index fell 0.6% in May from April as the prices of dairy products and vegetable oils dropped. Prices, however, were still 56.2% higher than a year ago.

Wheat prices, meanwhile, rose by 5.6% in May compared to the previous month. 

They "rose in response to an export ban announced by India and concerns over crop conditions in several leading exporting countries as well as reduced production prospects in Ukraine due to the war," the FAO said.

Citing inflation and its own food security needs, India banned last month any new wheat exports without government approval after the hottest March on record - blamed on climate change - hit harvests.

Vegetable oil prices fell 3.5% in part due to Indonesia lifting an export ban on palm oil, the FAO said.