In a letter addressed to top executives, a group of Microsoft workers is demanding the company drop a controversial contract with the United States Army.

The workers object to the company taking a $479 million contract last year to supply tech for the military’s Integrated Visual Augmentation System, or IVAS. Under the project, Microsoft, the maker of the HoloLens augmented reality headset, could eventually provide more than 100,000 headsets designed for combat and training in the military. The Army has described the project as a way to “increase lethality by enhancing the ability to detect, decide and engage before the enemy.”

“We are alarmed that Microsoft is working to provide weapons technology to the US Military, helping one country’s government ‘increase lethality’ using tools we built,” the workers write in the letter, addressed to CEO Satya Nadella and president Brad Smith. “We did not sign up to develop weapons, and we demand a say in how our work is used.”

The letter, which organizers say included dozens of employee signatures at publication time, argues Microsoft has “crossed the line into weapons development” with the contract. “Intent to harm is not an acceptable use of our technology,” it reads. The workers are demanding the company cancel the contract, stop developing any weapons technology, create a public policy committing to not build weapons technology, and appoint an external ethics review board to enforce the policy. While the letter notes the company has an AI ethics review process called Aether, the workers say it is “not robust enough to prevent weapons development, as the IVAS contract demonstrates.”

Microsoft has faced internal criticism in the past over its work with the US government. Last year, after it was revealed that the company was providing services to Immigration and Customs Enforcement, hundreds of employees quickly signed on to an open letter demanding the company end its relationship with the agency. Still, Microsoft executives have defended their government work, and the company did not accede to employees pushing to stop work with ICE.

“As employees and shareholders we do not want to become war profiteers,” the letter sent today concludes. “To that end, we believe that Microsoft must stop in its activities to empower the U.S. Army’s ability to cause harm and violence.”

In a statement, a Microsoft spokesperson pointed to an October blog post on the issue, and said the company has given it “careful consideration.”

“We always appreciate feedback from employees and provide many avenues for their voices to be heard,” the spokesperson said. “In fact, we heard from many employees throughout the fall. As we said then, we’re committed to providing our technology to the US Department of Defense, which includes the US Army under this contract. As we’ve also said, we’ll remain engaged as an active corporate citizen in addressing the important ethical and public policy issues relating to AI and the military.”

The Army contract demand is the latest example of tech industry workers organizing against their companies’ plans. Last year, Google employees banded together to push back on plans to work on a Pentagon AI project called Project Maven. Under pressure, Google leadership eventually backed off from the plan. More recently, employees at several tech companies have pressed executives on issues like sexual harassment policies and the development of facial recognition.

The full letter from the Microsoft workers is below:

Dear Satya Nadella and Brad Smith,

We are a global coalition of Microsoft workers, and we refuse to create technology for warfare and oppression. We are alarmed that Microsoft is working to provide weapons technology to the U.S. Military, helping one country’s government “increase lethality” using tools we built. We did not sign up to develop weapons, and we demand a say in how our work is used.

In November, Microsoft was awarded the $479 million Integrated Visual Augmentation System (IVAS) contract with the United States Department of the Army. The contract’s stated objective is to “rapidly develop, test, and manufacture a single platform that Soldiers can use to Fight, Rehearse, and Train that provides increased lethality, mobility, and situational awareness necessary to achieve overmatch against our current and future adversaries.”. Microsoft intends to apply its HoloLens augmented reality technology to this purpose. While the company has previously licensed tech to the U.S. Military, it has never crossed the line into weapons development. With this contract, it does. The application of HoloLens within the IVAS system is designed to help people kill. It will be deployed on the battlefield, and works by turning warfare into a simulated “video game,” further distancing soldiers from the grim stakes of war and the reality of bloodshed.

Intent to harm is not an acceptable use of our technology.

We demand that Microsoft:

 1) Cancel the IVAS contract;

 2) Cease developing any and all weapons technologies, and draft a public-facing acceptable use policy clarifying this commitment;

 3) Appoint an independent, external ethics review board with the power to enforce and publicly validate compliance with its acceptable use policy.

Although a review process exists for ethics in AI, AETHER, it is opaque to Microsoft workers, and clearly not robust enough to prevent weapons development, as the IVAS contract demonstrates. Without such a policy, Microsoft fails to inform its engineers on the intent of the software they are building. Such a policy would also enable workers and the public to hold Microsoft accountable.

Brad Smith’s suggestion that employees concerned about working on unethical projects “would be allowed to move to other work within the company” ignores the problem that workers are not properly informed of the use of their work. There are many engineers who contributed to HoloLens before this contract even existed, believing it would be used to help architects and engineers build buildings and cars, to help teach people how to perform surgery or play the piano, to push the boundaries of gaming, and to connect with the Mars Rover (RIP). These engineers have now lost their ability to make decisions about what they work on, instead finding themselves implicated as war profiteers.

Microsoft’s guidelines on accessibility and security go above and beyond because we care about our customers. We ask for the same approach to a policy on ethics and acceptable use of our technology. Making our products accessible to all audiences has required us to be proactive and unwavering about inclusion. If we don’t make the same commitment to be ethical, we won’t be. We must design against abuse and the potential to cause violence and harm.

Microsoft’s mission is to empower every person and organization on the planet to do more. But implicit in that statement, we believe it is also Microsoft’s mission to empower every person and organization on the planet to do good. We also need to be mindful of who we’re empowering and what we’re empowering them to do. Extending this core mission to encompass warfare and disempower Microsoft employees, is disingenuous, as “every person” also means empowering us. As employees and shareholders we do not want to become war profiteers. To that end, we believe that Microsoft must stop in its activities to empower the U.S. Army’s ability to cause harm and violence.

Microsoft Workers

Update, 8:31PM ET: Includes statement from Microsoft spokesperson.