Hackers target social media network Facebook
Facebook has said it was the target of an unidentified hacker group earlier this month, but found no evidence that user data was compromised.
The social network website site said: "Facebook was not alone in this attack. It is clear that others were attacked and infiltrated recently as well."
The website claims to have more than one billion active users worldwide.
Facebook's announcement follows recent cyber attacks on other prominent websites.
Twitter said earlier this month that it had been hacked, and that approximately 250,000 user accounts were potentially compromised.
Attackers gained access to information including user names and email addresses.
Newspaper websites, including those of The New York Times, Washington Post and Wall Street Journal, have also said they have also been infiltrated.
Those attacks were attributed by the news organisations to Chinese hackers targeting their coverage of China.
While Facebook said no user data was compromised, the incident could raise consumer concerns about privacy and the vulnerability of personal information stored within the social network.