BANGKOK, Thailand (AP) — The world's rush to embrace biofuels is causing a spike in the price of corn and other crops and could worsen water shortages and force poor communities off their land, a U.N. official said Wednesday.

Speaking at a regional forum on bioenergy, Regan Suzuki of the U.N.'s Food and Agriculture Organization acknowledged that biofuels are better for the environment than fossil fuels and boost energy security for many countries.

However, she said those benefits must be weighed against the pitfalls — many of which are just now emerging as countries convert millions of acres to palm oil, sugar cane and other crops used to make biofuels.

"Biofuels have become a flash point through which a wide range of social and environmental issues are currently being played out in the media,'' Suzuki told delegates at the forum, sponsored by the U.N. and the Thai government.

Foremost among the concerns is increased competition for agricultural land, which Suzuki warned has already caused a rise in corn prices in the United States and Mexico and could lead to food shortages in developing countries.

She also said China and India could face worsening water shortages because biofuels require large amounts of water, while forests in Indonesia and Malaysia could face threats from the expansion of palm oil plantations.

"Particularly in the Asia-Pacific region, land availability is a critical issue,'' Suzuki said. "There are clear comparative advantages for tropical and subtropical countries in growing biofuel feed stocks but it is often these same countries in which resource and land rights of vulnerable groups and protected forests are weakest.''

Initially, biofuels were held up as a panacea for countries struggling to cope with the rising cost of oil or those looking to reduce greenhouse gas emissions. The European Union, for example, plans to replace 10 percent of transport fuel with biofuels made from energy crops such as sugar cane and rapeseed oil by 2020.

But in recent months, scientists, private agencies and even the British government have said biofuels could do more harm than good. Rather than protecting the environment, they say energy crops destroy natural forests that actually store carbon and thus are a key tool in the fight to reduce global warming.

Some of those doubts were on display Wednesday at the U.N. forum, with experts saying many countries in Asia have rolled out plans to mandate biofuels for transport without weighing the potential risks.

Thailand, for example, is considering delaying the introduction of diesel blended with 2 percent biofuel for two months until April because of palm oil shortages, while the Philippines is considering shelving a biofuels law over concerns about the negative environmental effects.

India is facing criticism that its plans to plant 30 million acres of jatropha trees by 2012 for biofuel could force communities from their land and worsen deforestation. There are also concerns that it will be unable to find the 100 million acres of vacant land it needs to grow the shrub-like plants.

Varghese Paul, a forest and biodiversity expert with the Energy and Resources Institute in India, said dependence on a single species is dangerous.

"An outbreak of pests and diseases could wipe out entire plantations in one stroke,'' Paul said.