US Air Force via Airman 1st Class Madeleine E. Remillard (Image credit: Madeleine E. Remillard)

Microsoft CEO Satya Nadella has responded to recent criticism over Microsoft's contract with the US military for an "Integrated Visual Augmentation System," or basically a HoloLens for military use, saying it was "principled decision."

"We made a principled decision that we're not going to withhold technology from institutions that we have elected in democracies to protect the freedoms we enjoy," Nadella told CNN Business at Mobile World Congress.

Nadella's comment comes after some employees protested the contract via an open letter addressed to him and Microsoft president Brad Smith. The letter, titled "HoloLens For Good, Not War," demands that Microsoft cancel the IVAS contract and calls for the appointment of an independent, external ethics review board.

"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 'videogame', further distancing soldiers from the grim stakes of war and the reality of bloodshed," the letter states.

HoloLens has made more headlines than usual in recent days and weeks. In addition to blow back over the military contract, which was awarded last November, Microsoft today lifted the wraps on a second generation model, HoloLens 2. The latest generation of HoloLens more than doubles the field of view, is purportedly more comfortable, and costs $3,500.