Hoping to challenge the popular iPhone and carve out a dominant position in the transition of the internet to mobile networks, Google launched its first mobile phone Tuesday in the United States in conjunction with the German-owned carrier T- Mobile.

The new device, called the T-Mobile G1, functions on 3G networks and is specially designed to access popular Google services such as search, Gmail, maps with directions, and YouTube at high speed.

It also features a touch screen and a slide out keyboard - a feature that could give it an advantage over the iPhone.

The T-Mobile G1 is manufactured by Taiwanese electronics maker HTC and features the Android operating system that had been developed by teams of Google engineers over the last three years. Android is an open source system than can be used and changed by any device manufacturer.

Google, which currently dominates advertising on the internet, hopes that Android will become the standard operating system for increasingly sophisticated mobile phones, which experts believe will provide the main access to the internet for billions of people without computers.