China on Thursday stepped up accusations that Google is spreading obscene content, a day after U.S. officials urged Beijing to abandon plans for controversial filtering software on new computers.

The quarrel over control of online content threatens to become another irritant in ties at a time the world is looking for the United States and China to cooperate in helping to pull the global economy out of its slump.

China's Foreign Ministry on Thursday accused Google's English language search engine of spreading vulgar content that violated the nation's laws, less than 24 hours after brief disruptions to the company's search engines and other services within China.

Spokesman Qin Gang did not directly answer a question about whether official action was responsible for the disruptions, but he made plain the government's anger and said various punishment measures taken against Google were lawful.

I want to stress that Google China is a company operating within China to provide Internet search services and it should strictly abide by Chinese laws and regulations, he told a regular scheduled news conference.

U.S. Commerce Secretary Gary Locke and U.S. 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.

China says the Green Dam filtering software is to protect children from illegal images and insists the deadline of July 1 for 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 U.S. 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 U.S. officials said.

GOOGLE DISRUPTED

The software plan coincides with criticisms of Google by China's Internet watchdog and access disruptions in China to the U.S. 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 on Wednesday evening, 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, but an official newspaper reported on Thursday that a plan to recruit volunteers to scour the Internet for banned content and report to officials will also have a political element.

The Legal Daily reported that 10,000 volunteers sought by Beijing would also search for harmful content that includes threats to state security, subverting state power, and spreading rumours and disturbing social order.

Lu Jun, a human rights activist in Beijing involved in opposing the software filter plan, said China's drive to control the Internet may assume an increasingly political tone.

I think their real fear is how the Internet has become a launching point for so many rights campaigns, said Lu.

The Green Dam software is faulty now, but once installed it can be constantly upgraded to strengthen its controlling functions.

(Additional reporting by Mohammad Zargham in Washington, Emma Graham-Harrison in Beijing and Lucy Hornby in Shanghai; Editing by Ken Wills and Dean Yates)

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