Experts have warned that online access is "totally down" in North Korea as the nation experiences serious internet problems.
It is not immediately clear if the internet connectivity problems were an act of retribution for a major intrusion at Sony Pictures Entertainment which the FBI last week linked to North Korea.
The White House declined to comment on the problems but State Department spokeswoman Marie Harf told reporters that of the federal government responses, "some will be seen, some may not be seen".
North Korea has threatened strikes against the White House and the United States mainland, calling the country a "cesspool of terrorism" and accusing Barack Obama of spreading "reckless" rumours about its involvement in a cyber-attack on Sony Pictures.
Such rhetoric is not unusual from Pyongyang's massive propaganda machine during times of tension with Washington.
But the long statement from the powerful National Defence Commission also underscores Pyongyang's sensitivity at a movie whose plot focuses on the assassination of its leader Kim Jong Un, the beneficiary of a decades-long cult of personality built around his family dynasty.
"Our toughest counter-action will be boldly taken against the White House, the Pentagon and the whole US mainland, the cesspool of terrorism, by far surpassing the 'symmetric counter-action' declared by Obama," said the commission's policy department, in a statement carried by the official Korean Central News Agency.
The US blames North Korea for the cyber-attack that escalated to threats of terror strikes against American cinemas and caused Sony to cancel The Interview's release.
China has said it opposes all forms of cyber attacks and "cyber terrorism" in the wake of the massive Sony Pictures security breach.
Beijing's Foreign Minister Wang Yi made the denouncement to US Secretary of State John Kerry via a phone call, Reuters have reported.
"China opposes any country or person using other nations' internal facilities to conduct cyber attacks on third-party countries." Wang Yi reportedly told Kerry.
Last week, the US concluded that North Korea, one of China's global allies, was responsible for the attack on Sony Pictures.
President Barack Obama is considering the possibility of putting North Korea back on the US' terror list following the recent cyber attack on Sony Pictures.
Obama has said one option available to him is to punish North Korea for its act of "cyber-vandalism" by putting the country back on a list of state sponsors of terrorism, from which Pyongyang was removed six years ago.
The Obama administration is consulting the UK, Australia and New Zealand, among other countries in hopes of organizing an international response to the cyber-attack on Sony Pictures that it has pinned onNorth Korea, a White House official told Reuters.
The US is also consulting South Korea, Japan, China and Russia for help reining in North Korea.
A hacker group who claimed to be behind a cyber attack on Sony Pictures have posted a message online apparently mocking the FBI.Read the full story ›
The United States has dismissed North Korea's offer to help with a joint investigation into hacking of Sony Pictures.
"If the North Korean government wants to help, they can admit their culpability and compensate Sony for the damages this attack caused," National Security Council spokesman Mark Stroh said.
"As the FBI made clear, we are confident the North Korean government is responsible for this destructive attack. We stand by this conclusion."
"The Government of North Korea has a long history of denying responsibility for destructive and provocative actions," he said.
North Korea has warned the US government of 'grave consequences' if they refuse to take part in a joint probe into the recent Sony cyber attack.
A warning was also issued to the US to stop making accusations suggesting North Korea was involved in the attack, Korea's central news agency reports.
ITV News Correspondent Amy Welch reports:
North Korea have proposed conducting a joint investigation with the US into the cyber attack on Sony's computer systems.
The Korean Central News Agency reports that the nation's government can prove it has nothing to do with the hacking attack.
Hollywood actor George Clooney has said the entertainment industry should push for immediate release of The Interview online.
Not because everybody has to see the movie, but because I'm not going to be told we can't see the movie.
That's the most important part.
Here, we’re talking about an actual country deciding what content we’re going to have. This affects not just movies, this affects every part of business that we have.
That’s the truth. What happens if a newsroom decides to go with a story, and a country or an individual or corporation decides they don’t like it?
Forget the hacking part of it. You have someone threaten to blow up buildings, and all of a sudden everybody has to bow down.
Clooney told the trade site Deadline that Sony should "do whatever you can to get this movie out".