Hackers apparently based in Iran have mounted a three-year campaign of cyberespionage against high-ranking U.S. and international officials, including a four-star admiral, to gather intelligence on economic sanctions, antinuclear proliferation efforts and other issues, according to cybersecurity investigators.

Using an elaborate ruse involving more than a dozen personas working for a fake U.S. news organization, the hackers developed connections to their targets through websites like Facebook and LinkedIn to trick them into giving up personal data and logon information, the investigators say. The alleged campaign, which dates back at least to 2011 and is still under way, principally has focused on U.S. and Israeli targets in public and private sectors.