Microsoft has expanded its legal battle against Linux seller Lindows, suing the software maker for trademark infringement in Canada.

A Microsoft representative confirmed that the suit has been filed in the Federal Court of Canada in Ottawa.

The suit makes trademark claims similar to previous cases filed in the United States and Europe and seeks an injunction barring Lindows from doing business under that name.

The U.S. suit, filed shortly after Lindows went into business, claims the company's name infringes on Microsoft's trademark for its Windows operating system. Lindows, which sells a version of the open-source Linux operating system with an interface similar to Windows, argues the Microsoft trademark is invalid because "window" was a generic computing term at the time it was granted.

The judge hearing the U.S. cases has sided with Lindows in denying Microsoft's requests for an injunction against the company. The judge also recently ruled in Lindows' favour in declaring that the jury must consider use of the term "windows" around the time the trademark was granted. Microsoft plans to appeal that decision, further delaying the trial.

Microsoft has filed similar legal actions in several European countries, where it has been more successful with injunction requests.

Lindows CEO Michael Robertson said Microsoft is expanding the case globally mainly as a punitive business tactic against a competitor.

"We've been selling to Canadian customers for more than two years, and Microsoft hasn't said a word," he said. "This is just trying to pile on lawsuits to slow us down."

The Microsoft representative said Microsoft must protect its trademarks to retain them. "Microsoft's actions in Canada are only about the Lindows name," the representative said.