There's a motto at Google: "Don't be evil."

Today, more than 3,000 Google employees fear their company is on the verge of breaching that code by helping the U.S. military improve its spy drone software.

According to The New York Times, some 3,100 Google employees, "including dozens of senior engineers," have signed a letter to company CEO Sundar Pichai, demanding that Google immediately cancel their partnership with the U.S. Department of Defense (DOD) on a drone program known as Project Maven.

"We believe that Google should not be in the business of war," the letter states. "Therefore 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 22 Weirdest Military Weapons]

Project Maven, which Google signed onto last month, fits into the DOD's larger goal of improving America's ability to "[win] wars with computer algorithms and artificial intelligence," DOD officials said in a statement. Google agreed to help with this mission by developing artificial intelligence software capable of rapidly scanning thousands of hours of surveillance drone footage and automatically detecting "38 classes of objects" that military analysts regularly look for.

Despite a Google spokesperson's assurance that their new tech would be "for non-offensive uses only," many Google employees were instantly wary of the partnership, Gizmodo reported. In the new complaint letter, which is currently circulating within Google, employees voiced their concerns about the tech's potential applications in warfare. "The technology is being built for the military," the letter says, "and once it’s delivered it could easily be used to assist in [lethal] tasks."

"By entering into this contract, Google will join the ranks of companies like Palantir, Raytheon, and General Dynamics," the letter continues. "The argument that other firms, like Microsoft and Amazon, are also participating doesn’t make this any less risky for Google… Building this technology to assist the US Government in military surveillance – and potentially lethal outcomes – is not acceptable."

According to Engadget, Google Communications provided a statement when reached for comment about the letter.

"An important part of our culture is having employees who are activelyengaged in the work that we do," the statement read. "We know that there are many open questions involved in the use of new technologies, so these conversations — with employees and outside experts — are hugely important and beneficial."

The statement made no indication that Google intends to cancel their contract with the DOD.

Originally published on Live Science.