Google has partnered with the United States Department of Defense to help the agency develop artificial intelligence for analyzing drone footage, a move that set off a firestorm among employees of the technology giant when they learned of Google's involvement.

Google's pilot project with the Defense Department's Project Maven, an effort to identify objects in drone footage, has not been previously reported, but it was discussed widely within the company last week when information about the project was shared on an internal mailing list, according to sources who asked not to be named because they were not authorized to speak publicly about the project.

Google's Eric Schmidt summed up the tech industry's concerns about collaborating with the Pentagon at a talk last fall. "There's a general concern in the tech community of somehow the military-industrial complex using their stuff to kill people incorrectly," he said. While Google says its involvement in Project Maven is not related to combat uses, the issue has still sparked concern among employees, sources said

Project Maven, a fast-moving Pentagon project also known as the Algorithmic Warfare Cross-Functional Team (AWCFT), was established in April 2017. Maven's stated mission is to "accelerate DoD's integration of big data and machine learning." In total, the Defense Department spent $7.4 billion on artificial intelligence-related areas in 2017, the Wall Street Journal reported.