Microsoft (search) Corp. said Tuesday it has filed 15 lawsuits against people and companies it claims have collectively flooded its systems and customers with more than 2 billion deceptive, unsolicited e-mail messages.

The lawsuits address some of the most misleading, deceptive and offensive spam e-mail received by Microsoft customers, the company said. The lawsuits accuse the companies of violating laws in Washington state and the United Kingdom (search).

Microsoft cited a Washington law that allows Internet service providers to take action against spammers.

"Today's lawsuits are exactly the kinds of action we need to put illegal spammers out of business," said Washington Attorney General Christine Gregoire (search), who joined company officials at a news conference near Microsoft's Redmond headquarters.

In London, Microsoft announced a regional anti-spam initiative that includes two lawsuits alleging the unlawful gathering of e-mail addresses and other practices that violate U.K. law.

Microsoft is seeking court orders to stop the spammers and requests unspecified monetary damages, general counsel Brad Smith said.

Representatives of the companies either could not be located for comment or did not return messages left by The Associated Press Tuesday.

Washington state's anti-spam law bans bulk or commercial e-mail with misleading information in the subject line, invalid reply addresses or disguised transmission paths. It allows for damages of at least $500 per message for individuals and $1,000 for Internet service providers.

Earlier this year, Microsoft sought unsuccessfully to weaken provisions of the law by capping the amount that could be awarded to $25,000 a day, saying it wanted to protect itself and other service providers from people seeking to hold them accountable for spam.

But the hefty financial penalties were among the reasons Microsoft decided to sue under Washington's anti-spam law, said Tim Cranton, Microsoft's senior corporate attorney.

Microsoft's suits follow similar ones filed by rival Internet service providers America Online and EarthLink Inc.