Piracy activists have carried out coordinated attacks on websites owned by the music and film industry.
The assault temporarily knocked the Motion Picture Association of America (MPAA) and the Recording Industry Association of America (RIAA) offline.
The attacks were declared on notorious message-board 4chan and were reportedly in retaliation for anti-piracy efforts against file-sharing websites.
The group has declared it will continue to target other sites.
Next in their sights is the British Phonographic Industry (BPI), which it has said will come under attack on 20 September.
BBC News