Some top international food scientists Tuesday recommended halting the use of food-based biofuels, such as ethanol, saying it would cut corn prices by 20 percent during a world food crisis.

But even as the scientists were calling for a moratorium, President Bush urged the opposite. He declared the United States should increase ethanol use because of national energy security and high gas prices.

A story from the AP says, the conflicting messages Tuesday highlighted the ongoing debate over food and fuel needs.

The three senior scientists with an international research consortium pushing a biofuel moratorium said nations need to rethink programs that divert food such as corn and soybeans into fuel, given the burgeoning worldwide food crisis. The group, CGIAR, is a global network that uses science to fight hunger. It is funded by dozens of countries and private foundations.

If leading nations stopped biofuel use this year, it would lead to a price decline in corn by about 20 percent and wheat by about 10 percent from 2009-10, said Joachim von Braun. He heads the International Food Policy Research Institute in Washington, the policy arm of CGIAR. The United States is the biggest biofuel producer.

He and the other scientists said work should be stepped up on the use of non-grain crops, such as switchgrass, for biofuel.