Exploiting worries over the swine flu outbreak, spammers flooded the Internet on Monday with millions of e-mails peddling counterfeit drugs as remedies and seeking to steal credit card data, a security firm said.

Many of the e-mails direct recipients to websites for fake online pharmacies, according to McAfee Inc, the world's second-largest security software maker.

They offer promised treatments for the virus.

You are not getting what you think you are buying, said the firm's director of research, Dave Marcus.

In some cases, the websites simply use the ploy to steal credit card data or to deliver counterfeit drugs, Marcus said.

McAfee estimated that the swine flu spam, which began trickling out over the weekend, accounted for 3 to 4 percent of all e-mail spam on Monday.

Governments around the world rushed to reduce the impact of a possible flu pandemic on Monday as a virus that has killed 103 people in Mexico and spread to the United States and Canada also reached Europe.

(Reporting by Jim Finkle; Editing by Will Dunham)