Google employees have joined Amnesty International in calling for the company to cancel “Project Dragonfly,” an initiative to create a censored search engine for China.

What’s happening? On a “global day of action” coordinated by Amnesty International, over 35 Google employees have signed an open letter calling for Google to abandon the project. “Our opposition to Dragonfly is not about China: we object to technologies that aid the powerful in oppressing the vulnerable, wherever they may be,” the letter says. The signatories warn it could create a “dangerous precedent at a volatile political moment” and make it harder for Google to deny similar concessions to other countries. They also raise specific concerns about technology-enabled surveillance in China and the oppression of Uighurs, women’s rights advocates, and students.

Some background: Many Googlers have been unhappy about the project since it was first revealed by the Intercept in August. The news led to resignations, and 1,400 allegedly signed a letter in September demanding to know more. CEO Sundar Pichai confirmed the project’s existence last month but defended it as part of Google’s mission to provide information to everyone.

Employee activism: The open letter and protests at Google offices around the world are part of a growing trend of activism from staff at the big tech companies. Issues like discrimination against women, plus work with defense and immigration departments, have sparked major protests, culminating in walkouts at Google offices worldwide last month.