SAN FRANCISCO -- Google Inc. said Thursday that its search engine and other services were abruptly cut off from mainland China, raising more questions about the Internet company's ability to operate in the country while trying to work around the government's online censorship policies.
It's unclear why Google's search engine was suddenly fenced off, or whether China's government was blocking the service with technology tools known as the "Great Firewall."
The notice on Google's website reporting the China barrier provided no details and a spokesman at the company's Mountain View headquarters was unable to elaborate.
It's the first time Google has reported its search engine being completely blocked in mainland China since the company began posting public updates four months ago.
People in mainland China also were being prevented from using Google's mobile and advertising services, according to the company's status report. Other services, such as Google's blogging tools and YouTube video site, have been blocked in China for months.
The new barriers could signal China's communist government has finally decided to retaliate against Google for taking a stand against its effort to control what its citizens can see and read on the Internet. If that's the case, Google might have trouble maintaining and cultivating other services in the world's most populous country.
The relationship between Google and China's government has been tense since the company announced in January that it would no longer censor search results that the ruling party considered to be subversive or pornographic.
Google had cooperated with the government's restrictions for four years, but said it had a change of heart after uncovering a computer hacking attack that it traced to China.
Even as it took a moral stand, Google sought to keep a toehold in one of the Internet's most promising markets by automatically shifting search requests from mainland China to its service in Hong Kong, which doesn't fall under the same censorship rules.
But that detour eventually riled China's government, prompting another change that required visitors to Google.cn to click on the page to get to the Hong Kong search engine. That compromise paid off three weeks ago when China's regulators renewed Google's Internet license in the country for another year.
Even with that truce, some analysts wondered if China's government would still lash out at Google for its perceived defiance. Other analysts believed China would allow people to continue to click over to Google's Hong Kong search engine because it didn't want to discourage other technology companies from coming to the country.
China isn't a moneymaker for Google yet, accounting for an estimated $250 million to $600 million of Google's projected $28 billion in revenue this year.
But China is expected to become far more lucrative as its economy matures and even more of its population comes online. There is already more than 400 million Web surfers in China, exceeding the entire U.S. population.