“This report, if true, represents a whole new level of violation of our users’ privacy that is completely unacceptable and we strongly call on the world’s governments to reform surveillance law consistent with the principles we outlined in December,” the company said in a statement. “We are committed to preserving our users’ trust and security and continue our efforts to expand encryption across all of our services.”

Microsoft also said it had never heard of the surveillance program or the British government’s interest in using the Kinect camera for spying. “However, we’re concerned about any reports of governments surreptitiously collecting private customer data,” the company said in a statement. “That’s why in December we initiated a broad effort to expand encryption across our services and are advocating for legal reforms.”

Companies like Yahoo, Google and Microsoft that operate Internet services send vast amounts of data — including video and webcam chats — through the fiber-optic lines between their data centers around the world. After recent disclosures about government tapping of some such lines, all three companies have said they are working to encrypt those links between their data centers to thwart spying.

Yahoo has said that encryption will be in place for all of its services by March 31. Google has encrypted its video chat services, including Hangouts, since at least 2010.

Image British intelligence satellite dishes in Cornwall, England. Images from Yahoo webcam chats were captured in bulk through fiber-optic cable taps. Credit... Kieran Doherty/Reuters

In response to earlier concerns about potential government surveillance of the Kinect camera, Microsoft said last year that it would allow users to turn it off. It also said it did not give any government broad access to Skype data or security technologies.

Documents dated between 2008 and 2010 show the GCHQ was collecting still images from Yahoo webcam chats and storing them in an agency database. The GCHQ’s Optic Nerve program, which began as a prototype, was still active in 2012, according to an internal GCHQ document.