Tensions over trade frictions between China and the US heightened Wednesday with US trade authorities criticizing Beijing for imposing more trade restrictions in 2009, following confrontations over China's restrictions on the distribution of US films, music and books and the US' imposition of anti-subsidy tariffs on Chinese oil-well pipes.

Economic scholars observed that trade conflicts are a global issue rather than friction between China and the US against the background of a slow economic recovery.

"China continued to pursue industrial policies in 2009 that seek to limit market access for non-Chinese origin goods and foreign-service suppliers," the US Trade Representative's office said in its eighth annual report on how well China is complying with its World Trade Organization obligations.

The use of trade restraints and preferences, including export restraints, tax rebates, unique standards and the so-called "Buy China" policy, has been increasing during the past two years, the 121-page report said.

Intellectual property rights, trading rights, distribution services and the import of agricultural goods are also listed as the main areas of concern over China's adherence to ongoing WTO obligations.

China had a record $266 billion trade surplus with the US last year, according to government data. China is also the third-largest market for US exports, buying $70 billion worth of US-made products in 2008 compared to $19 billion in 2001, the trade office said.

China's Ministry of Commerce (MOC) could not be reached Wednesday. According to a quarterly review of trade released by the ministry Tuesday, China would maintain its export stimulus measures to tackle more complicated trade conditions next year after their success in offsetting the effects of the global economic crisis.

"Practice has proved that the policy mix to stabilize external demand is timely and effective. It has boosted market confidence and facilitated the steady recovery of foreign trade," it said.

The announcement came after the nation posted the best foreign trade performance in a year last month, rising 9.8 percent from a year ago after 12 consecutive monthly drops. The decline in exports narrowed to 1.2 percent in November while imports climbed 26.7 percent, year on year.

Since the crisis emerged, the government raised the tax rebate for exporters seven times and cut premium expenses to double export-credit insurance coverage, while introducing a fixed-rate yuan settlement in five cities in a pilot program to help exporters avoid the risks of exchange-rate fluctuations.