Beijing Google Inc., which withdrew its search engine from China in 2010 during a spat over censorship, is notifying users in the country if they type words or phrases that may disrupt connections to its sites.

Google searches from China have been “inconsistent and unreliable” for “the past couple years”, Google said in a statement posted on its website on Thursday. The company found no problems with its systems and concluded the interruptions were related to searches for particular terms, it said.

Web content in China is censored by the government to filter sites that contain pornography, gambling and content critical of the ruling Communist Party. Google said in January 2010 it wouldn’t self-censor content for Chinese services, so it shuttered its local search page and redirected users to a Hong Kong site.

Users of Google in China that search for such topics as the 1989 protests in Beijing’s Tiananmen Square or Tibet independence get error messages, including “This webpage is not available” and “The connection was reset”.

Google reviewed 350,000 of the most popular search terms in China and identified “disruptive queries”, the company said inThursday’s statement, which didn’t provide a full list of those words and phrases. Taj Meadows, a spokesman for the Mountain View, California-based company, declined to comment beyond the statement.

“Many of the terms triggering error messages are simple everyday Chinese characters, which can have different meanings in different contexts,” the company said in the statement.

The company cited two examples: the Chinese character jiang, which means “river”, and the character for zhou, meaning “week”. Google offered no explanation, though Jiang is the surname of former President Jiang Zemin and Zhou is the surname of Zhou Yongkang, China’s top internal security official.

Searches for some terms trigger a drop-down box saying they “may temporarily break your connection to Google. This interruption is outside Google’s control”.

Users then have the choice to edit the terms or continue the original search.