By CNN Staff
(CNN) -- Some official North Korean Internet and social media sites appeared Thursday to have been hacked, possibly by the hacker collective Anonymous.
The hacking -- including an image skewering North Korean leader Kim Jong Un on an official Flickr account -- comes amid rising tensions between North Korea and several other countries including the United States.
The North Korean government website Uriminzokkiri.com was down Thursday morning, and the official @uriminzok Twitter account -- also apparently tampered with -- has messages claiming that Uriminzokkiri, the Flickr site and other North Korean sites have been hacked.
Among the pictures on the Flickr account Thursday: A "wanted" poster with an image showing Kim with a pig's ears and nose.
The poster accuses Kim of "threatening world peace with ICBMs and nuclear weapons."
Another image reads: "We are Anonymous."
On the Twitter account, the usual image atop the page was replaced with one that reads "tango down" -- military slang that has been appropriated by hackers to say they have interrupted service to a website.
The image also shows dancers wearing Guy Fawkes masks. The mask is a favorite symbol of the hacker collective.
If it is the work of Anonymous, it would be appear to be just the latest attack by the group against North Korean sites. Last week, Anonymous, upon leaking account information from Uriminzokkiri.com, announced it would continue to hack North Korean sites if the government didn't "stop making nukes and nuke-threats," according to CNET.
The group also demanded the resignation of Kim, democracy in North Korea, and uncensored Internet access for all North Koreans, CNET reported.
Known for its DDOS, or distributed denial of service, attacks that take websites offline, Anonymous has taken up a number of causes. It had a hand in organizing and agitating in the Occupy movement throughout 2011. It also is known for defending WikiLeaks' Julian Assange and Assange's assertion that all information should be freely available on the Internet.
The hacker collective is an amorphous group that takes pride in not having a single leader or spokesperson, which makes claims by the group difficult to verify.
CNN's Jason Hanna and Ashley Fantz contributed to this story.
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