As many as a dozen Google employees quit their jobs Monday in protest over the company’s agreement to provide artificial intelligence technology to the Pentagon for use in improving weaponized drone strikes.

The U.S. Department of Defense initiative is known as Project Maven, and the resigning Google employees are concerned the company is helping the federal government use artificial intelligence to automate the process of classifying images of objects and people captured by drones. The project uses computer vision to autonomously extract objects from photos and video. The technology could be used to better identify human targets for strikes.

“The resigning employees’ frustrations range from particular ethical concerns over the use of artificial intelligence in drone warfare to broader worries about Google’s political decisions – and the erosion of user trust that could result from these actions,” the technology blog Gizmodo reported Monday.

Just last month, more than 3,000 Google employees signed a petition protesting