The UN has called for an immediate suspension of government-mandated US ethanol production, adding to pressure on President Barack Obama to address the controversial food-versus-fuel debate in the run-up to presidential elections.

Arguments for and against ethanol made from corn pit farming states such as Iowa – which benefit from higher corn prices and some of which are swing states – against livestock-rearing states such as Texas that see ethanol driving up their input costs.

The UN intervention will be seized on by state governors, lawmakers and the meat and livestock industry, who have expressed alarm at surging prices for corn. Group of 20 countries, including France, India and China, have already expressed concern about the US ethanol policy.