Nokia declared war in the US smartphone market with a Microsoft-powered handset tailored to take on Apple iPhones and Google-backed Android devices. Microsoft chief executive Steven Ballmer joined Nokia boss Stephen Elop to reveal the Finland-based mobile phone titan\'s plans to hit the US market in coming months, with a Lumia 900 smartphone designed for the media-gobbling habits. The price and release date for Lumia 900 was not disclosed, but it will be offered exclusively on the latest generation 4G LTE network of US telecom giant AT&T. Lumia 900 runs on Windows mobile software and will tap into the growing trove of hip, fun, or functional mini-applications for handsets based on Microsoft\'s latest mobile software. \"We believe the industry has shifted from a battle of devices to a war of ecosystems,\" Elop said. \"Clearly there are strong contenders on the field in this war of ecosystems,\" he told a room packed with press on the eve of the opening of CES expo in Las Vegas. \"With Lumia, we are establishing beachheads in countries and we will push forward with sales, marketing and successive products.\" Nokia in October introduced the Lumia line, which Elop described as the \"first real Windows phones.\" In a presentation loaded with war metaphors, Elop said that Nokia had used Lumia models to establish \"beachheads\" in Europe, India, and Hong Kong. The company planned to start the US invasion on January 11 with a Lumia 710 model that will be priced at $49 when bought with T-Mobile service contracts. \"The work Nokia is doing around Windows phone and this third ecosystem is really going to pay off,\" Ballmer said, caressing a sleek Lumia 900 touchscreen handset. \"When you pick it up and love and touch and feel your Lumia,\" he continued making a playful \'mmmmm\' sound that drew laughs, \"it really is quite fantastic.\"