United States Commerce Secretary Gary Locke said in Shanghai yesterday that Sino-American ties should have more quid pro quo, while signalling that some trade barriers may be lifted.

China needed to mend the "trade imbalance" with the US and boost liaison in matters related to clean and renewable energy, Locke said.

He also expected China to improve the foreign investment climate and pay more attention to the protection of intellectual property rights.

Locke pointed out that US exports to China had increased by a factor of 12 during the past 20 years, while imports from China had jumped more than thirty-fold, which "created some problems."

"The disagreements we have are an inevitable by-product of the growing and mature trade relationship between our countries," he said during a speech to members of the American Chamber of Commerce and the US-China Business Council.

The trade issue would be a major Strategic & Economic Dialogue topic in Beijing next Monday and Tuesday, he said.

For its trade surplus with the US, China argued the US had set in place rigid barriers for the exports of some sophisticated high technology that China eagerly wanted to buy.

Locke said yesterday the US planned to revamp its export-control regime and final results of the review would be released mid-summer.

"Worldwide, energy is a US$6-trillion market, and the fastest-growing sector is of the cleaner, greener kind," Locke said. "Both of our governments have committed to wide-ranging cooperation on clean energy."

Locke is leading a group of 24 US companies with a goal to advance exports of American technology related to clean energy in the areas of efficiency, storage, transmission and distribution.

Yesterday Locke attended a "greener future" signing ceremony between US design firm MulvannyG2 Architecture and two Chinese businesses to develop the Suning Plaza in Chengdu, capital of southwest Sichuan Province, and Xi'an Daming Palace in northwest Shaanxi Province.

Locke denied the US imposition of anti-dumping and countervailing duties on Chinese products was protectionism and said the disputes were not big enough to trigger a trade war.

"Although it's become something of a sport to portray every trade disagreement between the US and China as evidence of an impending trade war, it is important to remember that such disagreements cover a very small fraction of the trade between our two countries," he said.

Locke also said a big concern he heard from US firms was a perceived lack of transparence in China.

He said US businesses frequently did not understand China's regulations.