Washington ? Some of the nation’s largest Internet providers, in an unusual joint effort, said Wednesday they filed six lawsuits against hundreds of people who were accused of sending millions of unwanted e-mails in violation of the new U.S. law against spam.

The legal actions by Microsoft Corp., America Online Inc., Earthlink Inc. and Yahoo! Inc. represent the first major industry actions under the “can spam” legislation that went into effect Jan. 1. The lawsuits, filed in federal courts in California, Georgia, Virginia and Washington, were announced at a news conference.

The companies said the defendants included some of the nation’s most notorious large-scale spammers. The Internet providers — collectively with tens of millions of subscribers — said they shared information, resources and investigative information to identify some of the defendants.

“Congress gave us the necessary tools to pursue spammers with stiff penalties, and we in the industry didn’t waste a moment moving with speed and resolve to take advantage of the new law,” said Randall Boe, AOL’s top lawyer and executive vice president.

Dozens of those named in the lawsuits, however, were identified only as “John Doe” defendants who were accused of e-mailing unwanted pitches for prescription drugs, herbal potions and weight-loss plans.

Among the named defendants were Davis Wolfgang Hawke, of Medfield, Mass., whom AOL lawyers said also was known as Dave Bridger, and Braden Bournival of Manchester, N.H. They and others were accused of sending millions of e-mails offering weight-loss supplements, hand-held devices called “personal lie detectors” and other products.

The “can spam” legislation requires unsolicited e-mails to include a mechanism so recipients can indicate they did not want mass mailings.

The law also prohibits senders of unsolicited commercial e-mail from disguising their identity by using a false return address or misleading subject line, and it prohibits senders from harvesting addresses off Web sites.