As interruptions to Internet services in North Korea continue, speculations on who is causing the crashes have now included a popular hacking group that hinted that it was responsible.

Internet connections in North Korea were taken down early Tuesday, and it took almost 10 hours for the service to be restored.

The Internet shutdown prompted speculations that it was the United States government that was behind the cyberattack, as a form of retaliation against the hacking attacks carried out against Sony Pictures Entertainment.

The FBI has released the results of investigations that pin the hack on Sony Pictures on North Korea, with the controversial movie The Interview seen as one of the major motives behind the cyberattack on Sony.

The FBI also believes that it was North Korea that sent out anonymous e-mails that threatened violence on movie theaters that will show The Interview. Sony Pictures has already withdrawn the planned Dec. 25 release of the film, but eventually added that the movie will continue to show on a limited release for independent theaters.

President Obama issued a warning last week that the United States could look to respond "proportionally" against the attackers that victimized Sony Pictures, who have released confidential information into the Internet such as employee information, company secrets acquired through email accounts of top executives, and unreleased films.

In response, the defense department of North Korea said that it will "blow up" several targets in the United States, including the White House and the Pentagon, if the country received any form of retaliation.

North Korea has previously denied that it was behind the attack on the computer systems of Sony Pictures. However, Pyongyang said that the security breach was a "righteous deed" for the studio's production of The Interview.

The White House and the State Department have not responded to inquiries if the United States was behind the attacks that crashed the Internet in North Korea, which is only accessible by select members of the government.

Analyst speculations include the possibility that it was North Korea itself that took down its Internet networks, to be able to protect it from long-term damages and technical faults.

However, the Lizard Squad hacker group proclaimed through their Twitter account that taking down the Internet of North Korea was "a piece of cake." After a series of three tweets that hinted the group was behind the Internet outage of North Korea, the Lizard Squad account was suspended.

Other accounts by the Lizard Squad have since popped up on Twitter.

Analysts have said that the Internet crash in North Korea looks more like the work of tech vandals than that of the government, adding fuel to the speculations that it was indeed the Lizard Squad that caused the shutdown.

The Lizard Squad has become known for its DDoS attacks on gaming networks such as Xbox Live, which it took down early this month.