The EU has ordered Microsoft to separate the Internet Explorer from its PC operating system.

The abrupt reversal comes shortly before the European Commission is due to rule on antitrust charges brought against Microsoft in January, claiming that the world's largest software company abuses its dominant position by bundling its Internet Explorer browser, shielding it from head-to-head competition with rival products.

Until now, Microsoft has claimed that the browser was an integral part of the operating system and should not be pulled out, but it now plans to do that for a European version of Windows 7, due to be rolled out later this year.

The preliminary decision came after a yearlong investigation into complaints from a rival browser maker, Norway's Opera Software ASA, which said Microsoft's practices amounted to an unfair distribution advantage.

Since then, Mozilla Corp., which makes the Firefox browser, and Google Inc. have signed on as third parties against Microsoft in the case.

Microsoft's browser is the most widely used worldwide, but Firefox is gaining in popularity and Google, the top Web search provider, has released its own Web browser, Chrome.

"Given the pending legal proceeding, we've decided that instead of including Internet Explorer in Windows 7 in Europe, we will offer it separately and on an easy-to-install basis to both computer manufacturers and users," said Microsoft Deputy General Counsel Dave Heiner in a blog post on the company's website on Thursday.

European Union regulators, which had suggested Microsoft offer a choice of browsers on its operating system to open up choice for consumers, gave a frosty response.

"Microsoft has apparently decided to supply retail consumers with a version of Windows without a web browser at all," the European Commission said in a statement reacting to Microsoft's move. "Rather than more choice, Microsoft seems to have chosen to provide less."

The Commission is still weighing whether Microsoft's bundling of the browser has been abusive, and what sanctions to bring as a result. It is still possible that the Commission will force Microsoft to include other browsers with its operating system, a move the company has been determined to avoid.

Windows 7 is due out on Oct. 22. The Europe-only versions were described earlier by CBS Corp.'s CNET News.

Kutz said Microsoft will give computer makers the option to install IE on Windows 7 computers headed for Europe. It will also give PC users who want the browser a way to obtain it.

The EU has not yet issued its final decision. Microsoft requested a hearing to respond to the preliminary findings, but the parties could not agree on a date.