Google Inc. said many users in China were blocked from using its search service on Tuesday by a technical glitch that made their search queries appear to be associated with Radio Free Asia, which is blocked by Chinese authorities.
Google said the problem was triggered by changes it made to its own search code, and it is looking at how to resolve the problem.
Separately, it also said its mobile services in China were partly blocked on Sunday and Monday.
The news comes with Google's Chinese search service already in the headlines due to a censorship dispute with Beijing.
The company shut its mainland Chinese portal Google.cn last week and rerouted searches to its Hong Kong site in order to offer uncensored search results. But for most mainland Chinese, search results for sensitive terms like "Tiananmen" are still blocked by the Chinese government.
Users in China began on Tuesday to report erratic results on Google.com.hk, saying even searches for non-sensitive terms like "hello" returned blank pages. At other times, sensitive searches returned a normal result, showing links to pages that are then blocked by China's Internet filters.
Google said that due to a change on its site, "gs_rfai" started to appear in the URLs of Google searches globally in the last 24 hours.
"Because this parameter contained the letters rfa the great firewall was associating these searches with Radio Free Asia, a service that has been inaccessible in China for a long time -- hence the blockage," a Google spokeswoman said in an emailed statement. "We are currently looking at how to resolve this issue." Google said the problem affected "lots of" users.
Radio Free Asia is a pro-democracy, pro-human rights media channel that China's censors have blocked.
Google on March 22 said it would pull its Chinese-language search services out of China, citing also a hacking attack late in 2009 that it said originated from the country.
Google — the world's No. 1 Internet search provider and No. 2 in China behind local search powerhouse Baidu Inc. — has said it intends to retain some business operations in China, including research and development staff and a sales team.
But analysts have said that the Chinese government could make life difficult for Google.
According to Google, its mobile services were partly blocked in China for two days.
On a website showing the accessibility of Google's services in China, the company listed mobile as "partially blocked" on Sunday and Monday. Prior to Sunday, there were no issues with mobile services in China, according to the site — www.google.com/prc/report.html#hl=en.
Some users in Shanghai on Tuesday reported no problems with searching through Google's mobile service, indicating that the outages are intermittent.
Other mobile users have had problems ever since Google stopped censoring search results in China earlier this month.
A Google spokeswoman would not speculate on the cause for the mobile outages.
Google shares were up $1.67, or 0.3 percent, at $564.12 in late afternoon trade on Nasdaq.
© 2015 Thomson/Reuters. All rights reserved.