Amazon has filed lawsuits in the US and Canada against 11 companies that it alleges have stolen its identity to send out spam.

In what it said was a strong message to spammers, Amazon accused the companies in question of 'spoofing' - fooling people into thinking that the online retailer had sent them emails.

Spoofing is a favoured ruse for spammers. It allows them to place false address headers on emails to fool people into thinking they come from a legitimate company.

This makes the recepient more likely to open the message, and also makes it harder to trace the origin of the emails.

"Spoofers lie about who's really sending these emails," said Amazon's vice president, David Zapolsky.

"Spoofing is forgery and we're going after spoofers to the full extent of the law."

The company is seeking millions of dollars in punitive damages.

Zapolsky said that the company has set up a special email account, 'stop-spoofing@amazon.com', for customers to use to report suspected spoofing involving Amazon.com.

Amazon also reported that the New York Attorney General's office had settled civil fraud charges with one of the spoofers it identified.

Cyebye.com has promised to stop spoofing and to pay damages to Amazon. It will also have to keep records of all the commercial emails it sends during the next two years, and must provide the New York Attorney General's office with regular updates of its compliance with the settlement.