Popular social networking site Facebook was plagued by off-and-on service failures in several countries on Thursday night as well as Friday morning; and well-known hacking group, Anonymous, has claimed the credit for the intermittent outages.

According to a report by the tech outlet PC World, it was on late Thursday night that Facebook users in a number of areas - including Stockholm, Shanghai, Copenhagen, Oslo, Lisbon, San Francisco, and Moscow – first started complaining, on Twitter, about their inaccessibility to the social network.

The complaints - which continued to pour in till early Friday morning – indicated that Facebook was apparently hit by high response times and intermittent unavailability between 8:28 p. m. and 10:29 p. m. ET on Thursday, and between 3 a. m. and 6 a. m. on Friday.

Despite the fact that the actual reason behind the Facebook disruption still remains unclear, hackers claiming to have links with the Anonymous group said in a 15-minute video posted to the AnonNews website that the attack - code-named Operation Face Flood - said that they detested the way Facebook uses users’ personal information to make money. In addition, they also accused the social network removing Facebook pages set up by Anonymous.

Meanwhile, apologizing for the inconvenience which some Facebook users faced briefly in accessing the site on Thursday and Friday, Facebook spokesman Michael Kirkland said: "The issues have been resolved and everyone should now have access to Facebook.”