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US President Barack Obama has said that the US will respond to the Sony cyber-attack.Jim Bourg/Reuters

Barack Obama has waded into the Sony hacking scandal. The US President said that Sony Pictures "made a mistake" in the decision to cancel the release of The Interview following am alleged cyber-attack by North Korea.

Hackers had demanded that the movie which centres on a plot to kill North Korean leader Kim Jong-un, be shelved.

The film studio's systems were hit by a vast cyber security breach, which led to unidentified hackers leaking unreleased movies, private emails between senior executives, and confidential personal details of staff.

Reacting to the decision to cancel the film's scheduled release in December, the President said the United States cannot allow "some dictator" to impose censorship.

"We cannot have a society in which some dictator someplace can start imposing censorship in the United States. Americans cannot change their patterns of behaviour due to the possibility of a terrorist attack," he said. "That's not who we are, that's not what America is about."

He added that he wished the Hollywood studio had discussed the issue with him before deciding to withdraw the film.

Addressing reporters during an end-of-year news conference at the White House, he further offered an assurance that the US was prepared to respond to the cyber-attack, and a "proportional" response would occur "at a time and manner that we choose. They caused a lot of damage. And we will respond," he added.

Mr Obama also dismissed a report suggesting a possible Chinese connection to the hack either through collaboration or through the use of Chinese servers.

There is "no indication North Korea was acting in conjunction with another country", the President said.

Sony CEO Michael Lynton has reacted to President Obama's comments about the studio's decision to cancel the release of The Interview.

"We have not caved, we have not given in, we have not backed down," the 54-year-old Sony executive told CNN.

"I think the unfortunate part is... The President, the press, and the public are mistaken as to what actually happened. We do not own movie theaters. We cannot decide what will be played in movie theaters," he explained.

The President's comments came after the FBI announced it had concluded the devastating Sony hack was orchestrated by the North Korean government.

In a statement it said it was "deeply concerned about the destructive nature of this attack on a private sector entity and the ordinary citizens who worked there," adding that cyber attacks like this "pose one of the gravest national security dangers to the United States."

North Korea has denied any involvement in the incident.