Talks scheduled to be held in Puebla, Mexico, on March 18-19 had been postponed to April 22-23, but the divergence between Latin American nations and the United States forced another delay.

Ministers from North and South American countries in an informal two-day meeting were unable to reach an agreement on a text for the Puebla talks.

No new date has been set.

The free trade zone is scheduled to start in January 2005.

But a US official and Latin American ministers said they are determined to conclude negotiations on time.

"In reality there is no crisis," Brazilian negotiator Adhemar Bahadian said. "We are working cautiously to make progress and we will soon have positive results."

There are mainly differences over the subsidies the United States pays to its farmers.

"The subsidies are not justified," said Regis Arslanian, the chief of Brazil's delegation. "What is the use of a free trade zone in the hemisphere if the negative effects of subsidies on agricultural exports persist?"

US negotiator Peter Allgeier said there are also differences over anti-dumping measures, intellectual property and access to markets.

The United States proposed a cut in agricultural subsidies within the World Trade Organization (WTO), but Washington is concerned that some countries might take advantage of the subsidies' elimination, Allgeier said.