The European Commission said Wednesday that it was cutting targets for the use of biofuels so as to reduce the negative impact on food production and prices.
Critics said the measure did not go far enough while a UN official called for the European Union and the United States to abandon biofuels altogether as land used to produce them was needed by farmers to grow food instead.
The Commission said it would now limit the role of 'first generation' biofuels based on crops such as corn, beetroot or rapeseed so as to ease the pressure on food prices and encourage investment in non-food biofuels.
Accordingly, first generation biofuels would account for no more than 5.0 percent of transport sector energy use by 2020, up from 4.5 percent now and compared with an overall 10 percent target for renewables.
The balance of the 10 percent would be met by new biofuels based on non-food sources such as biomass or waste, or other renewable energy sources as in electric vehicles, the Commission said.
Cutting the target to 5.0 percent aims "to stimulate the development of alternative ... second generation biofuels from non-food feedstock ... which emit substantially less greenhouse gases than fossil fuels and do not directly interfere with global food production," it said.
To be effective, biofuels had to be "truly sustainable," said Commissioner for Climate Action Connie Hedegaard.
"We must invest in biofuels that achieve real emission cuts and do not compete with food," Hedegaard added in a statement.
The change comes after persistent criticism of the impact of biofuels on food production and prices, with food security emerging as a top item on the international agenda.
At the same time, recent research showed that some biofuel production was failing to deliver hoped-for reductions in greenhouse gases because changing land use to grow crops for energy had its own adverse impact on emissions.
As the changes were announced in Brussels, the UN's special rapporteur for the right to food, Olivier De Schutter, called on the European Union and the United States to stop using biofuels outright.
"Europe has to do more than lower its targets for production of biofuels as it is planning. It has to have the political courage to abandon them and the United States should do the same," De Schutter said.
"It is dangerous in a situation in which global cereal stocks are so low to set unattainable objectives," he said on the sidelines of a UN Food and Agriculture Organisation (FAO) meeting in Rome.
Explore further: Students learn first-hand about energy efficiency at school