Microsoft Corp launched two new phones aimed at young people on Monday, marking a fresh assault on the low end of the growing smartphone market, where BlackBerry maker Research in Motion Ltd and Apple Inc now dominate.

The software company's first foray into designing its own phones comes six months before it rolls out its new Windows software for phones made by handset makers HTC Corp, Samsung Electronics Co Ltd and others, which should be a more direct challenge to Apple's iPhone and Google Inc's Android phones.

The new phones launched on Monday, called Kin One and Kin Two, are made by Japan's Sharp Corp and will be sold by Verizon Wireless, a joint venture between Verizon Communications Inc and Vodafone Group Plc.

Both phones have a touch screen, slide-out keyboard and camera. Kin One is smaller, while Kin Two has a larger screen and keyboard, more memory and can record high-definition video.

The devices -- available in the United States in May and Europe in the autumn -- automatically bring together feeds from Facebook, MySpace and Twitter onto the homescreen and allow users to set up networks of friends to share photos, weblinks and so on.

Microsoft's Zune digital music player and FM radio is built into the phones. Almost everything on the phone is stored in the cloud, accessible from any Web browser.

The Kin service automatically backs up text messages, call history, photos, videos and contacts, in an attempt to soothe fears of data loss. Last October, users of Microsoft's Sidekick phones temporarily lost data due to a server failure.

Microsoft did not say how much the phones would sell for.

(Reporting by Bill Rigby and Gabriel Madway; editing by Phil Berlowitz, Lisa Von Ahn and Andre Grenon)