Google says it will stay in China if internet censorship is relaxed
US President Barack Obama continues to be "troubled" by alleged cyber-attacks originating in China on the internet search giant Google, officials say.
A White House spokesman said Mr Obama wanted "some answers" and agreed those responsible should "face consequences".
The comments came after China denounced US Secretary of State Hillary Clinton's criticism of its internet restrictions, saying it was harming relations.
Google has said it will decide shortly whether to end its China operations.
The company currently holds about one-third of the Chinese search market, far behind Chinese rival Baidu, which has more than 60%.
Earlier on Friday, a Chinese foreign ministry spokesman said the US should "respect the facts" and stop making "groundless accusations".
By Damian Grammaticas, Beijing
For China, the row sparked by Google has put it in an extremely uncomfortable position. It is under the harsh glare of US scrutiny on several sensitive issues: internet censorship, the silencing of dissidents and human rights campaigners, cyber attacks launched from China, and the difficulties big US companies find doing business in China.
Hillary Clinton's criticism of internet controls would have been pretty tough for Beijing to hear. So it is no surprise it has replied robustly. But China is on the back foot in this dispute.
The statement called on the US to "handle sensitive issues in an appropriate way". Decoded, that means China would rather it was all dealt with quietly, something that does not seem likely now the argument has become so public and far-reaching.
"The US has criticised China's policies to administer the internet, and insinuated that China restricts internet freedom," Ma Zhaoxu said.
"This runs contrary to the facts and is harmful to China-US relations."
The warning from Beijing came after Mrs Clinton said in a speech that the internet had been a "source of tremendous progress" in China, but that any country which restricted free access to information risked "walling themselves off from the progress of the next century".
The private sector had a shared responsibility to safeguard freedom of expression and should take a "principled stand" against censorship, she said.
Mrs Clinton also called on the Chinese authorities to investigate Google's complaint that hackers in China had tried to infiltrate its software coding and the e-mail accounts of human rights activists, in a "highly sophisticated" attack.
Hillary Clinton: "We look to the Chinese authorities to conduct a thorough review"
"Countries or individuals that engage in cyber-attacks should face consequences and international condemnation," she added.
Speaking to reporters on board Air Force One on Friday, White House spokesman Bill Burton made it clear that President Obama agreed with her.
"As the president has said, he continues to be troubled by the cyber-security breach that Google attributes to China," he said.
INTERNET ROW TIMELINE
12 Jan: Google says it may leave China after cyber attacks and calls for end to censorship of its search results
13 Jan: US says cyber attacks on Google "troubling"
14 Jan: China gives first reaction to Google statement: foreign firms welcome to work in China "according to law"
16 Jan: US says it will make formal protest over Google cyber attacks
21 Jan: China says its dispute with Google should not be linked to US relations
21 Jan: US Secretary of State Hillary Clinton criticises China's internet controls and urges Beijing to investigate Google attacks
22 Jan: China rejects Mrs Clinton's criticism as "groundless"
"All we are looking for from China are some answers," he added.
Chinese officials have repeatedly said that Google and other foreign internet companies are welcome to operate within China as long as they obeyed the country's laws and traditions.
When the California-based company launched google.cn in 2006, it agreed to censor some search results - such as the 1989 Tiananmen Square protests, Tibetan independence or Falun Gong - as required by the Chinese government.
Google now says it is looking at operating an unfiltered search engine within the law in the country, though no changes to filtering have yet been made.
China has more internet users - about 350 million - than any other country and provides a lucrative search engine market worth an estimated $1bn (£614m) last year.
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