North Korea said U.S. accusations that it was involved in a Sony cyberattack is "groundless slander" and proposed a "joint investigation" into the incident. (Reuters)

Threatening “serious consequences” if the United States continues to accuse it of launching a cyberattack against Sony Pictures, North Korea on Saturday proposed a joint investigation into the assault on the entertainment company, according to news reports.

U.S. analysts view the proposal as typical posturing by the North Korean government in an effort to appear sincerely interested in unraveling the origins of the attack, knowing full well that the United States would never agree to a joint investigation, according to the Associated Press.

“Whoever is going to frame our country for a crime should present concrete evidence,” a spokesman for North Korea’s Foreign Ministry said in a statement carried by the state-run Korean Central News Agency on Saturday, according to CNN. “America’s childish investigation result and its attempt to frame us for this crime shows their hostile tendency towards us.”

In a statement released Friday, the FBI announced that the agency had collected enough evidence to determine that the North Korean government — using “destructive malware” and a top-level Sony employee’s computer credentials — is responsible for the attack. The agency said the tools used in the attack are similar to those used in a North Korean attack on South Korean banks and media outlets in March 2013.

“Though the FBI has seen a wide variety and increasing number of cyber intrusions, the destructive nature of this attack, coupled with its coercive nature, sets it apart,” the agency’s statement said. “North Korea’s actions were intended to inflict significant harm on a U.S. business and suppress the right of American citizens to express themselves. Such acts of intimidation fall outside the bounds of acceptable state behavior. “

The massive hacking of Sony Pictures ranges from executives' e-mails disparaging actors to leaked personal information. The Post's Cecilia Kang explains what has been revealed so far, and why it could get much worse for the production company. (Jayne W. Orenstein/The Washington Post)

The spokesman for North Korea’s Foreign Ministry called the American allegations “groundless slander” and said he knows how to prove the country’s innocence, according to the AP. “The U.S. should bear in mind that it will face serious consequences in case it rejects our proposal for joint investigation and presses for what it called countermeasures while finding fault with” North Korea, the spokesman said.

“We have a way to prove that we have nothing to do with the case without resorting to torture, as the CIA does,” he said.

Koh Yu-hwan, a professor at Seoul’s Dongguk University, told the AP that this is not the first time North Korea has proposed a joint investigation during a conflict with a rival country. In 2010, Pyongyang offered to jointly investigate a torpedo attack that killed 46 South Korean sailors while denying its involvement in the attack, he said.

“They are now talking about a joint investigation because they think there is no conclusive evidence,” Koh told the AP. “But the U.S. won’t accede to a joint investigation for the crime.”

The group of hackers responsible for the attack called themselves the “Guardians of Peace,” according to the FBI. In addition to releasing thousands of confidential Sony e-mails and business files, threats of 9/11-style violence against American moviegoers led to theaters canceling showings of “The Interview” — a comedy based on a plot to kill North Korean leader Kim Jong Un — and Sony scrubbing the Christmas Day release. Sony’s decision was slammed Friday by Hollywood insiders and President Obama, who called the decision “a mistake.”

“I wish they had spoken to me first. . . . We cannot have a society in which some dictator someplace can start imposing censorship,” Obama said at a year-end news conference, speaking of executives at Sony Pictures Entertainment.

On Friday, Sony Pictures Chairman Michael Lynton told NPR’s Melissa Block that he was surprised by the president’s remark, but added that he thinks the two are both strong proponents of the First Amendment. He also said his company was forced to cancel the movie’s release because theaters across the country refused to show the film.

Sony Pictures has canceled the Dec. 25 release of "The Interview" after hackers threatened terrorists attacks and the largest multiplex chains in North America pulled the film from its screens. (AP)

“We did not capitulate,” he said. “We don’t own movie theaters, and we require movie theater owners to be there for us to distribute our film. We very much wanted to keep the picture in release. When the movie theaters decided that they could not put our movie in their theaters, we had no choice at that point but to not have the movie come out on the 25th of December. This was not our decision.”