Major North Korean websites were back online after being taken down for a couple of hours on Tuesday, according to CNN.
The United States also vowed retaliation for the Sony cyber attack, which the U.S. blamed on Pyongyang, CNN reported. Sony decided not to release the movie "The Interview" after threats from the hackers.
President Barack Obama has said the U.S. government expected to respond to the Sony hack, which he described as an expensive act of "cyber vandalism" by North Korea, according to Reuters.
There has been no confirmation or any denying from the American government on whether it had any involvement in the Internet shutdown in North Korea, according to CNN. North Korea blamed Seoul and Washington, D.C., for the outages.
North Korea Internet is not readily available for the masses. Only the elite are allowed to surf websites, but even those sites are limited to the country's domestic Intranet, Reuters reported.
North Korea is qualified to have broadband Internet, but only a small, approved segment of the population has any access to the World Wide Web, while more than a million people use mobile phones in North Korea, according to Reuters.
The Internet outage in North Korea began slowly, taking out more websites as it went on, according to Reuters. Some websites were offline for almost 10 hours, according to Reuters.
Pyongyang denies any involvement in the Sony Hack, but says it agrees that the movie should not have been released and expressed discontent with the fictional killing of North Korea's Kim Jong Un in the movie, Reuters reported.
Possible causes for the shutdown in North Korea include an external attack on its fragile network or simple power problems, according to Reuters. North Korea suffered similar brief Internet shutdowns of websites at a time of nuclear tensions with the U.S., South Korea and other countries.
The options for retaliation against North Korea are limited because it already faces massive international and U.S. sanctions over its repeated nuclear and rocket tests, Reuters reported.
