Mozilla has issued a broadside against Microsoft’s upcoming Windows 7 operating system, by claiming it stifles the browser market and gives Redmond’s Internet Explorer an unfair advantage over its rivals.

According to the Financial Times, Mozilla’s chairwoman Mitchell Baker said: "Our initial review suggests this is a blatant use of the Windows operating system to change the market dynamics of browser usage."

"What we've seen so far is a clear example of why and how Microsoft's Windows monopoly damages competition in related products," she claimed.

Microsoft rejected her comments and said the release candidate version of Windows 7 was only intended for hardcore testers to play with.

The latest spat follows Microsoft’s response to the anti-trust arm of the European Commission, which in January issued preliminary findings that accused the software vendor of unfairly bundling its IE browser with its Windows operating system.

Norway-based browser maker Opera, which brought the original IE complaint against Microsoft to Brussels, also took a swipe at the company’s tactics.

"This issue highlights the problem with the browser market," Opera's chief technology officer Hakon Wium Lie told the FT. "It's certainly something we would want to discuss."

The EC could order Microsoft to distribute rival browsers alongside IE when bundled in its Windows operating system. A response from Brussels is expected next month. ®

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