The news that Google plans to develop a censored search engine for China has drawn the ire of human rights activists, digital rights organizations, and even its own employees. And so far, the details that have trickled out about the project only seem to reinforce concerns that Google is willing to put aside one of its most valued ideals—free speech—in order to appease the Chinese government.

In addition to censoring search results for sensitive topics like political dissidents, a prototype of Google’s Chinese search engine, codenamed Dragonfly, reportedly links users’ queries to their phone numbers, according to the Intercept, which last month broke the story about Google’s China plans. Google declined to comment on the development of its search engine for China.

There were already concerns the Chinese government would be able to monitor Google searches in the country because the company’s user data would be stored locally on the mainland. But the revelation that Dragonfly, which was designed for Android devices, is tying searches to phone numbers leaves little doubt the government has every intention to surveil its users on the internet. Such a feature could put Google users in China at risk of interrogation or detention if they’re found to be seeking information banned by the government.

Already, amid China’s brutal crackdown on Uyghur Muslims in Xinjiang, some members of the religious minority have said that merely receiving content deemed sensitive on their phones—as well as calls or text messages from people abroad—could land them in “re-education” facilities.

Google used to maintain a censored search engine in China but exited the country in 2010 because of the government’s attempts to limit free speech. Last month, Google’s senior research scientist Jack Poulson quit in protest after learning about the company’s China plans. “I am forced to resign in order to avoid contributing to, or profiting from, the erosion of protection for dissidents,” he wrote in his resignation letter. “I view our intent to capitulate to censorship and surveillance demands in exchange for access to the Chinese market as a forfeiture of our values.”

According to the Intercept, Chinese officials have already seen demos of various versions of Google’s search engine, and a final version could be launched by the first half of 2019.