Contention between China and the United States has spread to the Internet after Washington urged Beijing to abandon demands that personal computers sold in China from next week have filtering software.
US trade officials said China's plan could violate international trade rules, and the quarrel threatens to become another irritant in ties when governments are looking to the United States and China to co-operate in helping pull the world economy out of its slump.
In a separate case, the United States and the European Union said on Tuesday they were complaining to the World Trade Organisation over China's export curbs on some industrial raw materials. China rejected those charges, saying its policies were in line with WTO rules.
US Commerce Secretary Gary Locke and US Trade Representative Ron Kirk voiced their concerns over the "Green Dam" software in a joint letter to their Chinese counterparts.
"China is putting companies in an untenable position by requiring them, with virtually no public notice, to pre-install software that appears to have broad-based censorship implications and network security issues," Locke said in a statement yesterday.
China says the "Green Dam" filtering software is to protect children from illegal pornographic and violent images and has insisted the deadline of July 1 for all new computers to be sold with the software will not change.
An official at the Chinese Ministry of Commerce, which handles trade rows, said the ministry had no immediate response to the US criticism and referred questions to the Ministry of Industry and Information Technology, which also had no comment.
Critics have said the program, sold by Jinhui Computer System Engineering Co, is technically flawed and could be used to spy on Internet users and to block other sites that Beijing considers politically offensive.
"Protecting children from inappropriate content is a legitimate objective, but this is an inappropriate means and is likely to have a broader scope," Kirk said.
"Mandating technically flawed Green Dam software and denying manufacturers and consumers freedom to select filtering software is an unnecessary and unjustified means to achieve that objective, and poses a serious barrier to trade," Kirk added.
The proposed new rules raised fundamental questions regarding the transparency of China's regulatory practices and concerns about compliance with WTO rules, the US officials said.
The software plan coincides with criticisms of Google by China's Internet watchdog and access disruptions in China to the US company's websites.
The watchdog last week ordered the world's biggest search engine to block overseas websites with "pornographic and vulgar" content from being accessed through its Chinese-language version.
Late last night, Internet users in China were unable to open several Google sites for around an hour.
A company spokeswoman at Google in the United States said the firm was checking reports of problems with access in China.
Google's problems illustrate the difficulties faced by foreign Internet firms doing business in the world's largest online market while avoiding charges of censorship.
Chinese officials have said their Internet moves are driven by worries about exposing children to disturbing online images.
Reuters