Google is preparing a version of its search engine for China that blocks results Beijing considers sensitive, according to people familiar with the situation.

The initiative is code-named Dragonfly and is one of several options the company is pursuing for returning to China, the people said, while noting the timing is still up in the air. They asked not to be identified discussing private plans.

The move would mark an abrupt about-face by the Alphabet Inc. unit and a win for China's communist government, which suppresses free speech online. Google co-founder Sergey Brin, whose parents brought him to the U.S. to escape communist Russia, led a dramatic exit from mainland China in 2010 after the company refused to self-censor search content. Brin has since stepped back from day-to-day operations, and the internet giant is now run by Chief Executive Officer Sundar Pichai. Still, other Google employees were angered by the news Wednesday.