The United States' top trade official has urged China to become more active in world trade talks, saying Beijing's leadership is needed for negotiations to succeed.

Susan Schwab answers reporters' questions during Beijing press conference Tuesday

U.S. Trade Representative Susan Schwab says China should take a more active role in the talks, rather than continuing to let other countries take the lead.

Schwab told U.S. business leaders in Beijing Tuesday that the success of the talks was possible only with vigorous and positive Chinese participation.

The Doha round of talks, named for the capital of Qatar where negotiations began in 2001, was suspended last month after major trading countries failed to agree on cutting farm tariffs and subsidies.

Schwab says China has a major stake in the talks' success.

"If the Doha round is unsuccessful, it will be tempting for countries to rely on litigation rather than negotiation to achieve new market opportunities," she said. "In such a scenario, China's commerce would be particularly vulnerable to legal challenges over compliance with global trade rules."

Schwab was in Beijing for two days of talks, and met Monday with Chinese Commerce Minister Bo Xilai.

China's official Xinhua News Agency quoted Bo on Tuesday as saying China was willing to work with other countries to restart the Doha round. However, he said developed countries should act first by making "substantial contributions."

The report did not spell out what contributions China wanted the developed countries to make, or what Beijing is willing to do to help restart the talks.

Bills have been introduced in the U.S. Congress calling for increased tariffs and other protectionist measures against Chinese goods. Schwab said these reflected American concern about China's fast rise in the world trade system.

Schwab says China could alleviate these concerns by showing responsible leadership, and fulfilling all the commitments it made when it joined the World Trade Organization.

"US-China trade relations today still lack equity, durability, and the balance of opportunities it should provide," she said. "This disparity is due in part to China's failure to honor certain commitments, including its failure to adequately enforce intellectual property rights, its efforts to protect and support certain domestic industries, and its delay in fulfilling certain market-opening obligations."

She specifically urged China to open its banking, insurance, and auto parts industries further to foreign competition.