(Telecompaper) Facebook has announced the launch of free video calling via its Messenger VoIP app in the US, Canada, UK and 15 other countries. The new feature allows users to start a video call within an existing Messenger conversation by tapping the video icon in the corner of the screen. Video calling in Messenger is now available for iOS and Android users in Belgium, Canada, Croatia, Denmark, France, Greece, Ireland, Laos, Lithuania, Mexico, Nigeria, Norway, Oman, Poland, Portugal, the UK, the US and Uruguay, with more regions to be added in the coming months. Messenger has more than 600 million monthly users worldwide and, according to Facebook, accounts for around 10 percent of mobile VoIP calls worldwide.