(ATHENS) - Biofuels must be developed more selectively to prevent competition with food-related crops, but they are still an answer to climate change, United Nations and European Union officials said on Tuesday.

"There is a concern that perhaps some of the investment and engagement in some of the biofuel production...in some cases did not go in the right direction," said Christophe Bouvier, European regional director of the United Nations Environment Programme (UNEP).

"But I think it's a question of making sure that the correct biofuels are being promoted...we have to be vigilant," he said on the sidelines of a three-day conference on climate and energy security in Athens.

There are cases of crops such as corn where "productivity is very low" in terms of the energy consumed to produce fuel, Bouvier said.

But there are also crops such as sugar cane which "could be part of the solution" if grown "in the right places and with a sustainable production system," he said.

Speaking at the same conference, European Union Environment Commissioner Stavros Dimas said the EU was formulating new rules on biofuel development taking environmental and social concerns into consideration.

"The effects on the environment may not be all that beneficial, especially in the case of low-productivity biofuels," Dimas said.

Growing use of biofuels has been cited along with poor harvests due to drought, surging demand in Asia as living standards have risen, higher transport costs and trade restrictions for the rapid rise in food prices.

At least five demonstrators were killed Monday when Somali security forces fired at crowds protesting rising food prices in the capital Mogadishu and a fresh protest was held Tuesday.

Riots over soaring food costs also sparked riots last month in Egypt and Haiti as well as protests in other countries and restrictions on food exports in Brazil, Vietnam, India and Egypt.

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