WASHINGTON - The United States imposed new sanctions on North Korea in retaliation for a cyber-attack on Hollywood studio Sony Pictures.

In an executive order President Barack Obama authorized the US Treasury to place on its blacklist three top North Korean intelligence and arms operations, as well as 10 government officials, most of them involved in Pyongyang's arms exports.

Obama said he ordered the sanctions because of "the provocative, destabilizing, and repressive actions and policies of the Government of North Korea, including its destructive, coercive cyber-related actions during November and December 2014."

The activities "constitute a continuing threat to the national security, foreign policy, and economy of the United States," he added, in a letter to inform congressional leaders.

"The order is not targeted at the people of North Korea, but rather is aimed at the Government of North Korea and its activities that threaten the United States and others," Obama added.

The sanctions come after hackers penetrated Sony's computers in late November, stealing and releasing over the Internet employee information, unreleased films and an embarrassing trove of emails between top company executives.

The hackers -- a group calling itself Guardians of Peace -- then began to issue threats against the company over the looming Christmas release of the comedy film "The Interview", which depicts a fictional CIA plot to kill North Korea's leader. (AFP)