United Nations, Dec 23 (IANS/EFE): The US has termed as "absurd" North Korea's proposal to jointly investigate the cyber-attack on Sony Pictures since Washington believes Pyongyang was behind the attack.

US Ambassador to the UN Samantha Power, during a Security Council debate Monday on the human rights situation in North Korea, attacked the regime for the hacking incident.

"Not content with denying freedom of expression to its own people, the North Korean regime now seems intent on suppressing the exercise of this fundamental freedom in our nation," she said.

"North Korea also threatened the United States with 'serious consequences' if our country did not conduct a joint investigation with (the North Koreans) into an attack that they carried out. This is absurd," she added.

The ambassador further said that this was exactly the type of behaviour Washington expected from a regime that threatened to take "merciless countermeasures" against the US for a Hollywood comedy.

According to Washington, the cyber-attack was in response to Sony's scheduled Christmas release of "The Interview," a comedy about a plot to assassinate North Korean leader Kim Jong-un.

"We cannot give in to threats or intimidation of any kind," Power said, recalling that her country has on numerous occasions been threatened by North Korea.

On Friday, US President Barack Obama announced that the US would give a proportionate response to the cyber-attack on Sony.

After that announcement, several North Korean web pages in the country were inaccessible Tuesday for over nine hours.

Pyongyang has denied having a hand in the hacking incident, and said that it was prepared to lock horns with the US on all fronts, including over the internet.