US director of national intelligence James Clapper says the cyber attack against Sony demonstrated a new threat from North Korea.
Mr Clapper also warned that North Korea will continue the attacks against American interests unless the United States “pushes back”.
He made the remarks at a cyber-security conference at New York’s Fordham University.
Mr Clapper described meeting a top North Korean general last year when he went there to negotiate the release of two US prisoners.
He said the general would have been the one to give the green light for the attack on Sony.
Mr Clapper said the general made it clear that North Koreans believe their country is under siege by the US and that they are “deadly serious” about affronts to their “supreme leader”.