Microsoft CEO Steve Ballmer said his company expects payment from computer users who run Red Hat Linux because the open source operating system violates Microsoft's intellectual property rights.

"People [who] use Red Hat, at least with respect to our intellectual property, in a sense have an obligation to eventually compensate us," Ballmer said at a company event last week in London.

A video of Ballmer's speech appeared this week on a Microsoft U.K. Web site.

Microsoft has long claimed that Linux and other open source software programs violate its patents. Last year, the company struck a deal with Linux distributor Novell under which it indemnified Novell Linux users from any legal claims. In return, Microsoft gained the right to re-sell certificates for Novell's SUSE Linux at a mark-up.

Last week, Ballmer implied that users of Linux distributions from vendors other than those with which it has patent deals -- the list also includes Xandros and Linspire -- could be hearing from Microsoft. "We've spent a lot of money licensing patents," Ballmer said.

Ballmer said Microsoft would like to create "an intellectual property framework" that bridges the commercial software and open source worlds so that users know where they stand with regard to using certain software programs.

He may not get much cooperation from the open source community, however. Linux advocates insist that the open source OS doesn't step on Microsoft's intellectual property and have publicly challenged the company to specify exactly which patents it believes have been violated.

Microsoft has thus far declined to do so.