(Adds comments from Sony's lawyer; statement from North Korea)
By Steve Holland and Doina Chiacu
WASHINGTON, Dec 21 (Reuters) - U.S. President Barack Obama moved to prevent U.S. anger at North Korea from spiraling out of control on Sunday by saying the massive hacking of Sony Pictures was not an act of war but instead was cyber-vandalism.
Washington's longstanding dispute with North Korea, which for years has centered on its nuclear weapons program, has entered new territory with the accusation that Pyongyang carried out an assault on a major Hollywood entertainment company.
Obama and his advisers are weighing how to punish North Korea after the FBI concluded on Friday that Pyongyang was responsible. North Korea has denied it was to blame.
The U.S. president put the hack in the context of a crime.
"No, I don't think it was an act of war," he told CNN's "State of the Union" show that aired on Sunday. "I think it was an act of cyber vandalism that was very costly, very expensive. We take it very seriously. We will respond proportionately."
Obama said one option was to return North Korea to the U.S. list of state sponsors of terrorism, from which Pyongyang was removed six years ago.
North Korea vowed on Sunday to hit back against any U.S. retaliation.
"Our toughest counteraction will be boldly taken against the White House, the Pentagon and the whole U.S. mainland, the cesspool of terrorism, by far surpassing the 'symmetric counteraction' declared by Obama," according to North Korea state news agency KCNA.
The hack attack and subsequent threats of violence against theaters showing the film prompted Sony to withdraw a comedy, "The Interview," prepared for release to movie theaters during the holiday season. The movie depicts the fictional assassination of North Korean leader Kim Jong-un.
Obama and free speech advocates criticized the studio's decision, but Sony Pictures Entertainment CEO Michael Lynton defended it, saying U.S. theaters did not want to show it.
Sony lawyer David Boies said the Hollywood studio planned to release the movie at some point.
"Sony only delayed this," Boies said on NBC's "Meet the Press" on Sunday. "It will be distributed. How it's going to be distributed, I don't think anybody knows quite yet."
In the CNN interview, which was taped on Friday, Obama acknowledged that in a digitized world "both state and non-state actors are going to have the capacity to disrupt our lives in all sorts of ways."
"We have to do a much better job of guarding against that. We have to treat it like we would treat, you know, the incidence of crime, you know, in our countries."