A tweet, which was posted on the @Facebook Twitter account, said “Hi, we are O u r M i n e.”
The group OurMine was responsible for the hack.
Twitter and Facebook are refusing to delete the altered video.
Tech companies have stepped up efforts to tackle misinformation on their services ahead of next year's U.S. presidential elections.
The Saudi government recruited two Twitter employees to get personal account information of their critics, prosecutors said Wednesday.
Facebook's policy is to accept paid political ads from candidates without fact-checking them or censoring them, even if they contain lies.
Twitter is banning all political advertising from its service, saying social media companies give advertisers an unfair advantage in proliferating highly targeted, misleading messages.
Twitter has taken action to stop posts by some fringe groups. Ryan Eldridge, co-founder of Nerds on Call Computer Repair, spoke to KTVU News @ 4P about the developments.