GENEVA (AP) _ The United States came under strong pressure Tuesday to drop its ban on imported tuna from Mexico and Venezuela, whose fisherman allegedly slaughter more than 50,000 dolphins a year in landing their prized catch.

At a meeting of the General Agreement on Tariffs and Trade, the European Community and more than 30 other nations pushed for Washington to accept the findings of a GATT expert panel that said the ban was illegal and must end.

Conservationists, usually quick to slam the Bush administration's environmental record, rallied to Washington's cause.

The World Wide Fund For Nature warned the case set a dangerous precedent that could gut national environmental protection laws.

''International environmental agreements are few in number and slow in coming,'' said WWF's Charles Arden-Clarke. ''And GATT is trying to knock down unilateral environmental initiatives taken in the interim.''

Washington banned imports of yellowfin tuna from Mexico and Venezuela in 1990 on the grounds that an unacceptably high number of dolphins were killed in the tuna nets.

A GATT arbitration panel last year upheld Mexico's complaint that the ban was illegal under GATT rules. It said Washington had no right to take unilateral steps to try to protect the environment outside its own territory.

''A contracting party may not restrict imports of a product merely because it originates in a country with environmental policies different from its own,'' panel chairman Andros Szepesi told Tuesday's meeting.

Trade representatives from Japan, Argentina, Brazil, Canada, Thailand, Australia and Sweden were among those backing his views.

The EC, which asked for the issue to be put on the agenda, said the United States and Mexico should not be allowed to settle the row between themselves as at least 20 other countries were now affected by the U.S. restrictions.

Last week a U.S. federal court rejected an appeal from President Bush to delay action and ruled the ban should be widened to include any country importing tuna from Mexico and Venezuela, which in effect means EC nations and Japan.

Mexico, trying to wrap up a free trade agreement with its wealthy northern neighbor, had previously agreed to sort out the dispute privately with Washington rather than through the international channels of GATT.

Stung by allegations that it was an enemy to the environment, GATT last week issued a report painting its Green credentials.

It said increased world trade led to higher incomes, more scope for spending on environmental projects, a better access to low-polluting technologies.