Senate Republicans have asked environmental regulators to use their power to halt the country's plans to expand ethanol production amid rising food prices.

Twenty-four Republican sena-tors, including presidential candidate Sen John McCain of Arizona, sent a letter on Friday to the Environmental Protection Agency (EPA) suggesting it waive, or restructure, rules that require a five-fold increase in ethanol production over the next 15 years.

Congress passed a law last year mandating a ramp-up to 15 billion gallons of corn ethanol by 2015 and 36 billion by 2022.

Encourage farmers

But McCain and other Repub-licans said those rules should be suspended to put more corn back into the food supply for animal feed, and to encourage farmers to plant other crops.

"This subsidised (ethanol) program - paid for by taxpayer dollars - has contributed to pain at the cash register, at the dining room table, and a devastating food crisis throughout the world," said McCain, in a statement.

A spokesman for the EPA said regulators will consider the economic impact of renewable-fuel requirements when deciding whether to suspend the rules.

The agency has the power to waive or restructure federal requirements if they cause harm.