GENEVA, Dec. 1 (AFP) – Ministers meeting at a key WTO conference made renewed pledges to conclude long-running negotiations for a global trade pact, but also remained locked in differences on where concessions should come from.

The United States called Monday on developing countries to make ''meaningful market opening'' but Brazil said it was ''unreasonable'' to expect developing countries to be the only ones making further concessions in order to secure the Doha round of global trade talks.

Meanwhile, World Trade Organization (WTO) chief Pascal Lamy warned ministers gathered at a key meeting in Geneva until Wednesday that time was running out to secure the pact.

''Time is running out, and it is not credible at this stage to see issues in isolation from the work and the achievements of the past eight years,'' Lamy said in opening remarks Monday to ministers and high-level officials from 153 member states attending the WTO meeting.

World leaders have pledged to conclude the Doha Round of global trade negotiations by 2010, but little progress has been made.

Since the start of Doha talks in 2001, deadlines have been repeatedly missed amid differences between developed and developing economies over the level of cuts to agriculture subsidies and industrial product tariffs.

US Trade Representative Ron Kirk signaled that his country was prepared to enter the final stage of negotiations if developing nations hastened moves to open their rapidly growing markets.

''For our part, the United States negotiating team is ready to move into the endgame,'' he said.

Citing figures from the International Monetary Fund, Kirk said 58 percent of global economic growth between now and 2014 will be provided by China, India, Brazil, Argentina, South Africa and Southeast Asian countries.

''The creation of new trade flows and meaningful market opening, particularly in key emerging markets, is required to fulfill the development promise of Doha,'' he said.