North Korea has called US President Barack Obama a “monkey” after US cinemas released a comedy about a fictional plot to kill its leader, as it suffered another in a series of crippling internet outages that it has blamed on Washington.

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The isolated dictatorship’s powerful National Defence Commission (NDC) on Saturday threatened “inescapable deadly blows” over the film and accused the US of “disturbing the internet operation” of North Korean media outlets.

An online blackout earlier this week triggered speculation that US authorities may have launched a cyber-attack in retaliation for the hacking of Sony Pictures — the studio behind madcap North Korea comedy “The Interview”.

Washington has said the attack on Sony was carried out by Pyongyang.

It suffered another paralysing outage on Saturday evening which also affected telecommunication networks in the pariah state, according to Chinese state-run Xinhua news agency.

Respected cyber security firm Dyn Research said the internet blackout was “country-wide”.

“This time there wasn’t the hours of routing instability that presaged the outage like last time. Although it did flicker back on for a moment, and go back down and stay down,” said Doug Madory, director of internet Analysis with Dyn Research.

“If an outside force took it down again, it did it more efficiently than the previous incident.”

The NDC accused Obama of taking the lead in encouraging cinemas to screen The Interview on Christmas Day. Sony had initially cancelled its release after major US cinema chains said they would not show it, following threats by hackers aimed at cinemagoers.

“Obama always goes reckless in words and deeds like a monkey in a tropical forest,” a spokesman for the NDC’s policy department said in a statement published by the North’s official KCNA news agency.

“If the US persists in American-style arrogant, high-handed and gangster-like arbitrary practices despite (North Korea’s) repeated warnings, the US should bear in mind that its failed political affairs will face inescapable deadly blows,” the NDC spokesman said.

He accused Washington of linking the hacking of Sony to North Korea “without clear evidence” and repeated Pyongyang’s condemnation of the film, describing it as “a movie for agitating terrorism produced with high-ranking politicians of the US administration involved”.

The film took in $US1 million ($A1.08 million) in its limited-release opening day, showing in around 300 mostly small, independent theatres. It was also released online for rental or purchase.

The film, which has been panned by critics, has become an unlikely symbol of free speech thanks to the hacker threats that nearly scuppered its release.

The low-brow comedy revolving around the fictional assassination of North Korean leader Kim Jong-Un played to packed cinemas across the US.

A file sharing website reported the film had been illegally downloaded more than 750,000 times.

Online services for Sony’s PlayStation and Microsoft’s Xbox gaming consoles, which had decided to release the film online, went down Thursday, apparently attacked by hackers.

Microsoft’s online network for its Xbox gaming console was restored to nearly full service Friday but the PlayStation network remained down.

The cause of the outages in North Korea’s already limited internet access has not been confirmed. The US has refused to say whether it was involved in the shutdown.