N Korea's internet down; US retaliation suspected

North Korea’s Internet went dark for several hours amid rumours of US retaliation over its alleged hacking of a Hollywood studio, just as the pariah state came under attack at the UN over its rights record.

It was not clear who or what had shut down Pyongyang's web connections, but cyber experts said the country's already limited Internet went completely offline overnight from Monday to Tuesday local time.

Piling further pressure on Kim Jong-Un's regime, UN members debated North Korea's brutal treatment of its huge prison population after China, its only major ally, was rebuffed in a bid to shelve the issue.

US-based Internet analysts Dyn Research said Pyongyang's four online networks, all connected through Chinese telecom provider China Unicom, had been offline for nine hours and 31 minutes before services resumed on Tuesday morning.

Dyn Research said Pyongyang's very limited infrastructure could be vulnerable to power outages but the way it had collapsed "seems consistent with a fragile network under external attack".

US President Barack Obama and the FBI have accused North Korea of being behind the hacking of Sony Pictures, which decided to cancel the Christmas Day release of comedy film "The Interview".

Washington officials refused to comment on speculation that the North Korean Internet blackout was the first stage in what Obama has warned will be a "proportionate response" to the hack.

North Korea has angrily insisted that it had nothing to do with the theft and leaking of Sony company secrets nor threats against moviegoers, but it has also condemned Sony's madcap movie, which features a fictional plot to kill Kim.