President Barack Obama says the US is reviewing whether to put North Korea back onto its list of state sponsors of terrorism.

Mr Obama says the hi-tech attack against Sony Pictures Entertainment is not an act of war but is a very expensive example of cyber-vandalism.

The US blames North Korea for the attack.

Mr Obama told CNN's State of the Union that the US will examine the facts to determine whether North Korea qualifies for the terrorism sponsors list. North Korea was removed in 2008.

Sony has cancelled the release of a film that North Korea found offensive. The firm says it had no choice because cinemas would not show the film.

Mr Obama said, however, that had Sony spoken to him directly, he might have called the movie theatres to question their decision.