The hacking group OurMine posted on the Twitter and Instagram accounts for Facebook and Messenger, writing "even Facebook is hackable".
The accounts have now been restored.
OurMine claims its attacks are an attempt to show cyber vulnerabilities. In January it hijacked over a dozen accounts for teams in the US National Football League.
The group posted a statement on Facebook's Twitter account. "Hi, we are OurMine. Well, even Facebook is hackable but at least their security is better then Twitter."