Russia's state anti-monopoly service launched a probe of Microsoft Corp over cutbacks in supplies of the Windows XP operating system in Russia, it said on Thursday.

The agency said it thought Microsoft had violated antimonopoly legislation by cutting delivery of Windows XP to Russia both separately and pre-installed on personal computers, as well as in its pricing policy on the product.

Analysis of the market for various operating systems shows that the transfer to the new Windows Vista operating system is occurring while demand for the previous operating system, Windows XP, continues, the service said.

Demand for separately packaged and pre-installed versions of Windows XP is also confirmed by retailers and the number of orders from the government.

It said it would consider the case on July 24, 2009.

Microsoft's Moscow office said it had not received an official query from the anti-monopoly service.

We (have) always answered antimonopoly service questions in full and intend to continue this practice in future, Microsoft spokeswoman Marina Levina said by telephone.

The anti-monopoly service is regularly in contact with Russian companies but full-scale investigations are not common.

The suit bears no immediate resemblance to past antitrust claims against Microsoft, target of a U.S. antitrust lawsuit in the United States a decade ago, and which was fined 500 million euros ($708.4 million) by the European Commission in 2004 for anti-competitive behavior in media player and server software.

The commission later fined Microsoft an additional 900 million euros for non-compliance but the software maker is appealing against that ruling.

(Reporting by Maria Kiselyova in Moscow and Reed Stevenson in Amsterdam; writing by Melissa Akin; Editing by Hans Peters and david Holmes)

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