Facebook has launched an instant messaging service for mobile phones, similar to BlackBerry Messenger. The dedicated app, for iPhones and Android devices, allows users to contact individual friends or groups of people. Its release comes a month before Apple is due to unveil a similar product. Attention has been focused on mobile messaging recently because some of the London rioters were known to have used it to co-ordinate their movements. So far Facebook’s mobile messenger is only available in the United States, but it is expected to eventually roll out in other countries. The social network’s 750 million users already have the ability to send messages through the website, and on Facebook’s original smartphone app. Its new application adds the option to send directly to a mobile phone via SMS, and also to include location information.