Chinese Ambassador to the World Trade Organization (WTO) Sun Zhenyu on Wednesday voiced China's concerns over U.S. trade policies and urged the United States to respond to those concerns.

"While we have full confidence in further developing the bilateral economic and trade relations, China has some concerns about U.S. trade policies," Sun told a World Trade Organisation (WTO) review of U.S. trade policy in the past two years.

He said China's major concerns include the "twin deficits" of trade and finance, fulfillment of transparency obligations, fair implementation of anti-dumping measures and foreign investment restrictions in the service sector.

According to the ambassador, the United States, the most frequent user of the WTO dispute settlement mechanism, is always quick to demand compliance from others when WTO rulings are in its favor, but fails to meet WTO "prompt compliance" requirement when rulings are against its interests.

He also accused the U.S. of undermining the world trading system by using national security concerns "in an excessive way" to get around the rules, saying that had significantly affected the normal operation of international trade and foreign direct investment (FDI) flows.

"Recently the U.S. exerted pressure and imposed restrictions on inward FDI on account of national security, which prevent foreign companies from seeking merger and acquisition within the country. These have dealt heavy blows to members' confidence in the business environment of the U.S.," he said.

"By interpreting and applying WTO national security clauses in an excessive way, it has again seriously undermined the credibility of the multilateral trade regime, over which China is highly concerned," he stressed.

The ambassador also pointed out that it was not wise for the U.S. to restrict the export of high-tech products to China, as it had deprived many American high-tech enterprises of the opportunities to do business with China.

"This policy not only harmed the interests of American exporters, but also made trade deficit situation even worse between the two countries," he said.

The ambassador also criticized the frequent use of anti-dumping measures by the U.S., noting that quite a number of those practices are not consistent with WTO anti-dumping rules.

He also urged the U.S. to assume greater responsibility in pushing forward the Doha round of global trade negotiations, which is expected to conclude by the end of this year but still faces huge challenges.

The U.S. should make further steps forward in cutting domestic support for agriculture, thereby making due contributions to the progress of the Doha round negotiations, he said.

All WTO member undergo periodic reviews of their trade policies by the Geneva-based trade body, and China was not the only one to express concerns over the U.S. trade policy, especially its use of national security concerns as a reason to block trade deals.

The European Union, the United States' biggest trading partner, noted that there was a need to strike "a better balance" between security concerns and avoiding "unnecessary and costly burdens" to legitimate business in a statement to the WTO.