The loosely organized collection of cyber rebels said it attacked the FTC's consumer protection business center and the National Consumer Protection Week websites.
Both sites were replaced with a violent German-language video satirizing the Anti-Counterfeiting Trade Agreement, or ACTA.
ACTA was recently signed by several countries, but restrictions on online piracy have prompted a growing protest movement.
A call to the Trade Commission rang unanswered before business hours Friday. An email seeking comment was not immediately returned.
The organization's main home page appeared unaffected by the attacks.