Facebook's WhatsApp is adding fully encrypted video calling to its messaging app, following the U.S. election of Donald Trump as president last week that heightened fears of increased digital surveillance. WhatsApp adopted end-to-end encryption early this year, making it technically impossible for the company or government authorities to read messages or listen to calls.

The new video calling service will thus provide another means for people to communicate without fear of eavesdropping though WhatsApp does retain other data such as an individual's list of contacts.

Users can move around the thumbnail video showing what their correspondent sees and flick a video call in progress to the side to minimize it while checking texts or email.

Apple offers its FaceTime video calls to iPhone users, and Microsoft's Skype offers video calls on multiple platforms. But WhatsApp has built a massive installed base of mobile customers and has been steadily adding more features to what began as a simple chat applications.

After years of pledging that it would not share information about users with Facebook, which already has digital dossiers on its own 1.7 billion users, WhatsApp revised its privacy statement in August to say it would do exactly that.