President Bush is urging European nations to lift their ban on imports of genetically modified food, saying high-tech advances can help win the war on hunger. He spoke at an international biotechnology conference in Washington.

The president's message was clear: the ban is hurting the countries that need the most help. "Acting on unfounded, unscientific fears, many European governments have blocked the import of all new biotech crops. Because of these artificial obstacles, many African nations avoid investing in biotechnology, worried that their products will be shut out of important European markets," Mr. Bush said.

Mr. Bush said advanced biotechnology would enable the Africans and others to grow crops resistant to drought and disease with far greater yields. He said emergency aid can help fight hunger, but getting this new technology in the hands of farmers is essential to these countries.

"We should encourage the spread of safe, effective biotechnology to win the fight against global hunger," he said.

The president spoke to a very receptive audience: a gathering of scientists and officials from top biotechnology companies and laboratories around the world. Mr. Bush also used the occasion to push Congress to pass his "bio-shield" initiative. It is a plan to put billions of dollars into the development and production of vaccines and treatments that could be used in the event of a chemical or biological terrorist attack.

"Under project bio-shield, the government will have the spending authority to ensure that the most advanced vaccines and treatments are available to our people," Mr. Bush said.

Mr. Bush first announced the initiative in his State of the Union address in January. It calls for expenditures of almost $6 billion over 10 years.