HONG KONG — Warning that global trade talks risk failure, a broad group of countries including India, Brazil and Australia urged fellow WTO members today to refocus on the "core" issue of farm trade at negotiations that have seen more discussion of aid proposals for the world's poorest nations.

However, the issue of aid and development yielded the first sign of concrete progress from the World Trade Organization meeting in Hong Kong, with negotiators reaching agreement on duty-free, quota-free access for imports from least developed countries, Indian and Indonesian officials said.

The breakthrough ended an impasse over the issue that delayed progress in other areas.

Developing country members threw their support behind the proposal, accepting the limited exemptions for duty-free, quota-free access insisted on by some WTO nations, including Japan, the U.S. and Switzerland.

With the six-day conference entering its fourth day, members of the Group of 20 leading developing nations and the Cairns group of major food exporters issued a strong statement urging the EU and United States to open their markets to more farm imports.

"It is time for them to display leadership," said the groups, which represent 27 nations and more than half the world's population.

"Hong Kong will be a lost opportunity" unless progress is made on reducing agricultural trade barriers, the statement said. The G-20 is led by India and Brazil, while the Cairns group includes major agricultural powers Australia, Canada and New Zealand.

Many of the 149 countries participating in WTO talks in Hong Kong this week, meant to conclude trade negotiations launched in 2001 in Doha, Qatar, have accused the EU of blocking progress by refusing to make bigger cuts in its farm tariffs and subsidies. Developing countries say those trade barriers block access to wealthier nations' markets and threaten poor farmers' livelihoods.

Negotiators have been trying to salvage the Hong Kong talks from a collapse, by turning their focus to trade of manufactured goods and services, the other two key areas covered in the talks.