Homeowners across the U.S. are being targeted in a sophisticated scam in which callers pose as mortgage lenders to defraud people out of hundreds of thousands of dollars, the Federal Communications Commission warned Tuesday in a consumer alert.

The fraud involves operatives calling homeowners, who oftentimes had previously sought relief from their mortgage lender and thus were expected to be contacted, according to the FCC. The callers frequently know details about the homeowner, including their name, address and their current or former mortgage lending institution.

The fraudsters also spoof the caller ID number of the homeowner's actual lending institution, further convincing them of the call's legitimacy, the agency noted...