Facebook is testing a new feature in the Facebook Messenger app: Users will be allowed to send messages that disappear an hour after they're sent - ramping up the challenge to Snapchat. Tapping an hourglass icon on the top right of the screen in Messenger will allow users to send messages designed to vanish an hour after they are sent.

The feature was tested with some Android /Apple phone users in France and could be made available globally if it proves successful, according to Facebook.

Vanishing messages provides users a sense of being able to keep their conversations private.

Smartphone-messaging rival Snapchat has been already appealing for its messages disappear shortly after being viewed.

Facebook has been also testing a Messenger app virtual assistant dubbed "M" that the social network said goes beyond artificial intelligence programs already on the market. "M" completes tasks along with seeking out information at the behest of users.