Microsoft unveiled a new mobile phone operating system today as it seeks to regain ground lost to the iPhone, Blackberry and devices powered by Google's Android software.

Microsoft chief executive Steve Ballmer took the wraps off nine mobile phones powered by Windows Phone 7 (WP7) at an event at a loft in New York's Chelsea neighbourhood.

Ballmer said more than 60 mobile operators around the world will offer the devices, made by South Korea's Samsung and LG Electronics, Taiwan's HTC and Dell, the US computer giant, in more than 30 countries.

"We have built a different kind of a phone," Ballmer said. "We set out to build a phone that was thoroughly modern."

US telecom carrier AT&T showed off three devices which will sell for around USD 200 in the United States, about the same price as Apple's iPhone.

Another US carrier, T-Mobile, will offer two WP7-powered devices in November.

WP7 is Microsoft's first significant update to its mobile operating system in 18 months and its release comes on the heels of the disastrous launch of a "Kin" line of phones, which were pulled from stores after just two months.

Though mobile makes up only one per cent of Microsoft's revenue, the smartphone market is growing by around 30 per cent a year and the software behemoth is determined to remain a player in the sector.