As hundreds of protesters marched peacefully in the streets of Hong Kong, U.S. Trade Representative Rob Portman told delegates gathered in the convention hall that a failure to reach a sweeping treaty to lower trade barriers risks a slide into protectionism.

"The time to stop postponing the toughest work has arrived," Portman said. "I believe either we move forward or we risk moving backward toward protectionism that will stunt economic growth and harm the developing world the most."

EU trade chief Peter Mandelson - blamed by many for holding up the talks amid EU refusal to further cut farm tariffs and subsidies - told delegates that the world cannot afford to wait any longer to wrap up the so-called Doha round of talks, originally meant to conclude by 2004.

But he said the WTO's 149 members will not reach that goal unless negotiations move away from the sensitive topic of farm trade and strive to cut trade barriers on industrial goods and services.

"We will not succeed, in Hong Kong or after, if we continue to focus on only one part of the round," Mandelson said. "We cannot afford to wait again. When the finishing line is in sight, it is the time to quicken our pace."

The Dec 13-18 meeting was meant to draw up an outline for a global treaty by the end of 2006 to lower or eliminate trade barriers in agriculture, manufacturing and services. But talks have been bogged down amid accusations from poorer countries that the European Union, the U.S., Japan and other wealthy countries are offering insufficient cuts to their agricultural import tariffs and farm subsidies.

Portman also pressed negotiators not to leave Hong Kong without setting a date for another meeting early next year with the goal of setting up a framework to complete the talks.

"Although we may not achieve all we had hoped for this week, let us set another deadline to keep the pressure on," Portman said.