Microsoft this week denied that it is censoring Chinese-language Bing results in the U.S.

China-based advocacy group GreatFire.org reported(Opens in a new window) on Tuesday that Redmond’s search engine is censoring search returns “in order to exclude certain results.” That includes controversial topics in the Asian country, including the Dalai Lama and Bo Xilai, the former government official jailed for corruption.

“Our tests indicate that Microsoft has decided that its customers around the world … need not know the entire truth about China,” the site said. “If this practice continues, China will move one step closer to cleansing the Internet of information it does not want the rest of the world to know about.”

Microsoft did not immediately respond to PCMag’s request for comment, but told Reuters(Opens in a new window) that any censorship was a glitch.

“Due to an error in our system, we triggered an incorrect results removal notification for some searches noted in [GreatFire.org’s] report but the results themselves are and were unaltered outside of China,” Stefan Weitz, senior director for Bing, said in a statement.

There is no word on whether that error has been fixed.

A test by PCMag returned English-language Bing search results for “Dalai Lama” similar to those that appear on rival Google—”His Holiness the 14th Dalai Lama” official site, as well as links to Wikipedia, Facebook, and Twitter.

The spiritual leader’s name in Chinese (达赖喇嘛), however, returns different results (right), including a documentary from China’s state-owned broadcaster CCTV, and entries from Baidu Baike, the country’s heavily censored Wikipedia lookalike.

The country has a history of locking down any information that it deems “harmful to the state,” and U.S. Internet companies have had to come up with workarounds in order to operate in the region. In a bid to attract more foreign firms to China, the country reportedly relaxed certain Web regulations in a free trade zone within Shanghai, but the Internet is far from open for the average citizen.

In an official Bing Help Q&A(Opens in a new window) Microsoft said its search result removal process is complicated and requires official government authority. Only once proof is verified will the company comply with the request.

GreatFire.com isn’t buying it, though, saying that it doubts Bing’s censorship moves have been implemented “in strict accordance with Chinese law.” The site challenged Microsoft to “show us the ‘proof of the applicable law’ which government officials feel is being broken.”