China was officially admitted to the World Trade Organization Saturday in what the U.N. secretary-general describes as "a major historic event." But the five-day conference may be in trouble, as developing countries are voicing opposition to a new round of trade talks.

The United States is urging World Trade Organization members to agree to a round of new trade talks. But developing nations, led by India, are voicing opposition.

The WTO conference in Qatar's capital, Doha, is becoming a showdown of big versus small, rich versus poor, as the world's economy continues to weaken.

U.S. Trade Representative Robert Zoellick says it is important that nations be committed to opening markets, not closing them. Most economists agree freer trade will lead to an expansion of global markets, which could give the world's economy a much needed boost.

Developing nations, however, are resisting new trade talks until their concerns from the last round of global negotiations are addressed.

They are also deeply concerned about the European Union's desire to draft new environmental rules that, they believe would preclude them from selling their products in developed countries.

"There is opposition to negotiating new rules in the environment because many countries are of the view this may lead, through the back door, to so-called 'green protectionism'," said WTO spokesman Keith McCormick. "There's a feeling that any new rules that may be drafted here would, in some way, impede imports of agricultural products, particularly from developing countries. So that's a difficult issue."

In the meantime China, with the world's largest potential market, was admitted to the WTO Saturday. China had been pushing to gain entrance to the world body for 15 years.

U.N. Secretary General Kofi Annan described China's admission as "an event of historic proportions for the world trading system."

Sunday, Taiwan will be officially admitted to the WTO.