US President Barack Obama has authorised fresh sanctions on North Korea as the "first aspect of our response" to the Sony hack.

The sanctions affect three North Korean entities, including a government intelligence agency and a North Korean arms dealer, the Obama administration said.

The US is also imposing sanctions on 10 individuals who work for those entities or the North Korean government.

The executive order from Barack Obama is said to be "is a response to the Government of North Korea’s ongoing provocative, destabilizing, and repressive actions and policies, particularly its destructive and coercive cyber attack on Sony Pictures Entertainment."

In a letter informing congressional leaders of his executive order, Obama added the activities "constitute a continuing threat to the national security, foreign policy, and economy of the United States".

"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," Mr Obama added.

The White House has praised Sony for reversing its decision to pull comedy The Interview, which features a fictional assassination of North Korea's leader.

Sony Pictures initially pulled the film, following a cyber attack against the company and threats against theatres that agreed to show the film.

The hackers obtained and released sensitive internal emails involving senior executives at Sony Pictures.

Sony claimed it had had "no choice" but to cancel the release because cinema chains across the US had backed away from showing the film after the threats.

The film went on limited release in cinemas on Christmas Day, and has also been released on video-on-demand services.

Two weeks ago the FBI linked North Korea to the cyber attack, which was carried out in November.

The FBI statement to the press said: "The FBI now has enough information to conclude that the North Korean government is responsible for these actions [the Sony attack]."

North Korea has denied any involvement in the cyber attack, and has proposed a joint investigation with the US.

US sanctions against Pyongyang have been in place since the 1950s, and were tightened after three nuclear weapons tests.

The White House declined to comment last week on whether the US was behind a nearly 10-hour shutdown of North Korean websites last week.

Originally published at 19.35