Members of the World Trade Organization (WTO), already at odds over trade in farm goods, on Friday bickered over the level of customs duties to be applied to industrial products, WTO sources said.

They said developed countries wanted to limit the maximum level of their industrial customs duties to 10 percent and the tariffs of developing countries to 15 percent.

But poor countries argued that too much was being asked of them compared with the concessions rich countries were prepared to make in agricultural trade.

The figure proposed by developed countries "is not attainable, is not possible -- it's out," said Brazilian negotiator Clodoaldo Hugueney, as WTO members struggled to overcome differences that are preventing an agreement of the Doha Round of trade liberalization talks.

Brazil , India, South Africa, and several other emerging market countries proposed a maximum industrial tariff level of 35 percent for developing nations. That suggestion was shot down by the developed world, with the European Union representative, Eckart Guth, calling the 35-percent figure "astronomically high."

A number of developing countries, notably Chile and Mexico, also found the proposal unrealistic.

China , which joined the WTO in late 2001, meanwhile argued that relatively new members should be given a longer time to apply trade-opening measures. But the United States, without mentioning China by name, said it would not agree to allowing "a major country" to enjoy such a dispensation.

Negotiators hope to come to an agreement in principle on a Doha deal before the end of July.

The talks opened in late 2001 in Doha, the Qatari capital, and were to have concluded in 2004.

But a deep disagreement on the concessions each of the major parties must make has prevented substantial progress toward an accord.