"We believe that Google should not be in the business of war," reads the letter, which was obtained by The New York Times and published Wednesday.
The letter, which is currently being circulated on an internal communication server among Google employees and has been for "several weeks," has collected 3,100 signatures so far, according to the Times.
Employees are upset about a partnership between Google and the United States Department of Defense called Project Maven. The conflict was first reported by Gizmodo in March. Project Maven involves Google developing artificial intelligence surveillance to help the military analyze video footage captured by U.S. government drones "to detect vehicles and other objects, track their motions, and provide results to the Department of Defense," the letter explains.
Google employees want Pichai to formally end the partnership.
"We ask that Project Maven be cancelled, and that Google draft, publicize and enforce a clear policy stating that neither Google nor its contractors will ever build warfare technology," the letter states.
Google employees are concerned that the tech giant's involvement in the development of the technology will hurt the company's reputation.
"This plan will irreparably damage Google's brand and its ability to compete for talent. Amid growing fears of biased and weaponized AI, Google is already struggling to keep the public's trust," the letter says. "Google's unique history, its motto Don't Be Evil, and its direct reach into the lives of billions of users set it apart."