The National Defence Commission, the North's ruling body chaired by state leader Kim Jong Un, said Obama was responsible for Sony's belated decision to release the action comedy "The Interview", which depicts a plot to assassinate Kim.
"Obama always goes reckless in words and deeds like a monkey in a tropical forest," an unnamed spokesman for the commission said in a statement carried by the official KCNA news agency, using a term seemingly designed to cause racial offence that North Korea has resorted to previously.
In Hawaii, where Obama is vacationing, a White House official said the administration had no immediate comment on the latest North Korean statement blaming the United States for the Internet outages and insulting the president.
Sony cancelled the release of the film when large cinema chains refused to screen it following threats of violence from hackers, but then put it out on limited release after Obama said Sony was caving in to North Korean pressure.
Obama promised retaliation against North Korea, but did not specify what form it would take.
North Korea's main Internet sites suffered intermittent disruptions this week, including a complete outage of nearly nine hours, before links were largely restored on Tuesday.
But its Internet and 3G mobile networks were paralysed again on Saturday evening, China's official Xinhua news agency reported, and the North Korean government blamed the United States for systemic instability in the country's networks.
Dyn Research, a U.S. firm that monitors telecommunications infrastructure, said on Saturday that North Korea's Internet access had been restored after a national outage that lasted more than five hours.
Jim Cowie, Dyn's chief scientist, said it was a "sharp" outage that appeared to immediately sever access across the nation, and the restoration also appeared to be equally fast.
"It could have been something as routine as maintenance or it could have been a continuation of the things we saw in the past week, which looked more like attacks," Cowie said.
In its statement on Saturday, the North again rejected an accusation by the U.S. Federal Bureau of Investigation that North Korea was behind the cyberattack on Sony Pictures, and demanded the United States produce evidence for its allegation.
The National Defence Commission also dismissed U.S. denials of involvement in North Korea's Internet outages.
"The United States, with its large physical size and oblivious to the shame of playing hide and seek as children with runny noses would, has begun disrupting the Internet operations of the main media outlets of our republic," it said.
In a separate commentary, the North denied any role in cyberattacks on South Korea's nuclear power plant operator, calling the suggestion that it had done so part of a "smear campaign" by unpopular South Korean leaders.
A South Korean official investigating the attacks this week, which led to leaks of internal data from Korea Hydro and Nuclear Power, said Seoul was not ruling out North Korean involvement.
"The South Korean puppet authorities are working hard to link this case with (us), though the truth about it has not been probed," Minju Joson, the official publication of the North's cabinet, said in a commentary carried by KCNA.

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