North Korea threatened more attacks against the US government and other American institutions in the wake of the November 24 cyber attack on Sony Picture Entertainment, which resulted in the movie's release being cancelled, the Daily Mail reported on Sunday.

The country's government, which was outraged by the film showing a fictitious US plot to assassinate North Korean leader Kim Jong-un, claimed to have "clear evidence" that the US government engineered the project as a "propaganda" attack against the country.

In June, a spokesman for Pyongyang had called the film an "act of war".

Referring to the US as a "cesspool of terrorism", the Communist dictatorship said that it has already lashed out at the "citadels of the US imperialists", naming the White House and the Pentagon in particular.

"The DPRK (North Korea) has already launched the toughest counteraction," a release said.

"Nothing is more serious a miscalculation than guessing that just a single movie production company is the target of this counteraction," it added.

"The army and people of the DPRK are fully ready to stand in confrontation with the US in all war spaces including (the) cyber warfare space to blow up those citadels," the North Korean authorities said.

On Saturday, North Korea vowed to boost its defence capabilities, including nuclear capabilities, saying that denuclearisation of the Korean Peninsula had "lost its meaning" amid a hostile US policy.

However, North Korea continued to deny that it had anything to do with the original cyber attack. A group calling itself Guardians of Peace had taken responsibility for the cyber attack.

North Korea had termed the hacking attack a "righteous deed".

The US Federal Bureau of Investigation (FBI) had concluded that North Korea was behind the attack. The bureau cited malware linked to "other malware that the FBI knows North Korean hackers previously developed".

Kim Jong-un's officials responded by calling FBI's claims a "fabrication", and described US actions "gangster-like".

North Korean authorities termed the US the "chief culprit of terrorism" and said that while the US called for combating terrorism everywhere in the world, it schemed behind the scenes itself to incite terrorism in various countries.

US President Barack Obama described the hacking attack as an example of cyber-vandalism but did not say that it was an act of war. He also said that the US was once again considering the inclusion of North Korea in its list of countries that sponsor terrorism.

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