"Currently we do not have the information required to make ethically informed decisions about our work, our projects, and our employment", the letter read. The company left China eight years ago, under pressure from the country's censorship laws, and alleged hacking attempts by the government.
China has the world's largest internet audience but USA tech firms have struggled to take off in China due to content restrictions and blockages.
Google has always painted itself not just as a mission-driven organization, but also as a values-driven place to work.
Google declined to comment on the letter. It has said in the past that it will not comment on Dragonfly or "speculation about future plans".
The discussion was part of a regular meeting that is open to all employees.
Meanwhile, at this week's staff meeting at Google, the company's leadership answered a few questions about the project Dragonfly.
Trump connects Russian Federation probe, action on Brennan
If there were others that weren't, that we deemed necessary, we would certainly take a look and review those as well", Ms. Brennan's editorial was published after he vowed in a series of tweets overnight to continue to criticize Trump. "No.
The result: Google managers were handed a reason not to disclose any more information about the company's controversial plans to operate again in China, founder Sergey Brin was made to look like a victim.
Hundreds of employees have called on the company to provide more 'transparency, oversight and accountability, ' according to an internal petition seen by Reuters on Thursday. One Google employee who had stood to ask a question suddenly addressed whomever was surreptitiously leaking information.
The China petition says employees are concerned the project, code named Dragonfly, "makes clear" that ethics principles Google issued during the drone debate "are not enough".
China closely monitors the internet services and platforms its residents can access, with Facebook, YouTube, Twitter and many Western news sites blocked in the mainland.
Google shut down its Chinese search engine in 2010. A possible re-entry to China, according to current and former employees, is a sign of a more mature and pragmatic company. It has been actively seeking a way back into the country ever since. Google can ply its staff with all the free food and ping-pong tables it wants, but it looks like its employees' vigilance and righteousness aren't going anywhere any time soon. And it has introduced translation and file management apps for the Chinese market.
And that's likely why many inside Google appeared sympathetic to the sentiment expressed by the man at the mic. Complaining that Google management has kept workers in the dark about program's goals, employees are now challenging the company's apparent decision to cave to Chinese government censorship.