Lawsuits filed in several states say the sites illegally used logos from news outlets to mislead consumers.
Over the past seven days, the FTC filed complaints in federal courts in Illinois, Michigan, New Jersey, New York, Georgia and Washington. The complaints named 10 website operators and asked the courts to freeze their assets.
The defendants paid more than $10 million to advertise their fake news sites, the FTC said. It is not clear whether all the sites in question are connected.
Last year, the FTC filed a separate lawsuit against a Phoenix, Ariz. company for using fake celebrity endorsements to sell acai berry products.
Courts granted temporary restraining orders in some of the cases and many of the websites have been taken down.
The Associated Press contributed to this report.