A group of developing countries, led by Brazil and India, has rejected a plan by the U.S. and Europe for reducing import tariffs for agricultural goods.
The Group of 20, as they are known, calls the proposal "fundamentally flawed" and says it cannot be the basis of an agreement within the World Trade Organization.
Agriculture is seen as the major stumbling block in making progress on the WTO trade round. The trade group's 147 members have set a deadline of July to agree on the framework for negotiations, including the formula for tackling farm tariffs.