Washington ? The Bush administration accused the European Union of violating international trade agreements Tuesday in blocking imports of U.S. farm products through its long-standing ban on genetically modified food, which the United States contends is safe.

U.S. Trade Representative Robert Zoellick announced that the United States was filing a formal complaint with the World Trade Organization challenging the five-year moratorium after months of negotiations trying to get it lifted voluntarily. Also signing onto the complaint were Argentina, Canada and Egypt.

The administration has been under pressure for months from lawmakers, farm groups and the biotechnology industry to file the complaint over the Europeans’ ban on biotech imports. The administration had argued against the ban but had delayed filing a WTO case while President Bush assembled support for a war against Iraq.

House Speaker Dennis Hastert, R-Ill., has long sought such a complaint, and in March, Senate Finance Committee Chairman Charles Grassley, R-Iowa, and Montana Sen. Max Baucus, the panel’s senior Democrat, took the administration to task for delaying.

Agriculture Secretary Ann Veneman said the case was filed to help farmers wanting to plant genetically engineered crops.

“Farmers here and around the world must be assured that their products won’t be rejected simply because they used biotechnology,” she said.

EU officials questioned the action, saying it will further damage trade relations already strained by the U.S. decision to launch a war against Iraq despite opposition from members of the U.N. Security Council.

“It can only make an already difficult debate in Europe more difficult,” said Margo Wallstrom, EU commissioner for the environment.

The European Union started the ban because it doubts the safety of biotech foods, though the United States contends such food is safe.

In 1998, the United States exported $63 million worth of corn to the European Union, but the exports dwindled to $12.5 million last year.

“Europeans have to know that they cannot use this as a trade barrier against us,” said Mary Kay Thatcher, a lobbyist for the American Farm Bureau Federation.

Concerns grew last August when some southern African nations facing famine rejected U.S. food aid because it included genetically modified grain. Several countries later agreed to accept the products, but only after they had been milled.

Corn and soybeans that have been genetically designed to tolerate Monsanto’s Roundup herbicide are widely grown throughout the United States. Some biotech crops can help increase yields and others are resistant to common field pests.

The Agriculture Department estimates that 38 percent of the 79 million acres of corn planted this year will be genetically engineered varieties. Biotech soybeans will cover 80 percent of this year’s anticipated crop of 73.2 million acres.

Gregory Conko, director of food safety policy for the Competitive Enterprise Institute, said farmers in developing countries have been unfairly hurt by Europe’s restrictions on genetically modified imports.

“I think that the impacts go far beyond our borders,” said Conko. “If the case is in fact resolved favorably, and if the European Union ends its moratorium and revises its other biotech regulations, you could see the birth of a real biotech revolution.”