The National Association of Securities Dealers issued an investor alert on Tuesday warning of stock scams that reference phony government regulator Web sites.

These unsolicited investment pitches are often ploys to get investors to send money in advance of any service rendered and are mainly targeting non-U.S. investors through e-mail and facsimile, the NASD reported.

The alert highlights particular investment pitches referencing “official” Web sites that are, in fact, phony. The latest twist involves sites using “-gov.us” in the Web address to resemble the “.gov.xx” designation that official government Web sites outside the U.S. typically use, where “xx” is a 2-letter country code. The alert also explains these fake sites may use “cookies” to track visitors and gather personal information.

The NASD says it is aware of at least three sites using the “-gov.us” trick: Central Registry Regulators, the National Mergers and Acquisitions Board, and the Board of Commissioners of Mergers & Acquisitions.

“What we are seeing is a new trick to lend legitimacy to money-making ‘advance fee’ schemes by fraudsters in the international arena,” said NASD senior executive vice president Elisse Walter. “It is important that investors — both in the U.S. and abroad — be wary of these investments scams and if they suspect they are being targeted call or e-mail their regulator.”