The Department of State, Office of Visa Services, advises the public of a notable increase and reporting of fraudulent emails and letters sent to Diversity Immigrant Visa (DV) program (Visa Lottery) applicants. The scammers behind these fraudulent emails and letters pose as the U.S. government, and attempt to extract payment or favor from DV applicants. We strongly encourage you to review the procedures for the DV program provided below, so that you know what to expect, when to expect it, and from whom. Remember that the Diversity Visa (DV) Program website is the source of official information about the DV program.
Link: http://travel.state.gov/visa/immigrants/types/types_1322.html