North Korea has been experiencing trouble with Internet connectivity. The outages occurred amid an ongoing row over a cyber attack on Sony and President Barack Obama's vow for retaliation.
By early Tuesday, Internet accessibility had returned in North Korea after the country experienced widespread outages.
"I haven't seen such a steady beat of routing instability and outages in North Korea before," Doug Madory of New Hampshire-based Dyn Research, a company that monitory worldwide Internet access, told the North Korea Tech blog. He speculated that North Korea was "absorbing some sort of attack."
The White House and the State Department declined to say whether the US government was responsible.
US President Barack Obama had vowed on Friday to respond to the Sony Pictures cyber attack, which he blamed on North Korea, "in a place and time and manner that we choose." He also said Washington was considering whether North Korea should be classified as a state that sponsors terrorism.
In North Korea, the majority of citizens do not have access to Internet connections, so it is expected that only the country's elite and a few schools were affected by the outage.
Row over Sony hack
The row between the US and North Korea happened after a cyber attack last month on Sony Pictures which gained access to and leaked thousands of company documents.
A hacker group calling itself "Guardians of Peace," then threatened violence to anyone attending a showing of the Sony film "The Interview," which mocks North Korea, and whose New York premiere was subsequently cancelled for security reasons.
While Pyongyang denied launching the attack, it said the hack was "a righteous deed of all the supporters and sympathizers with" the Democratic People's Republic of (North) Korea.
"Without resorting to such tortures as were used by the US CIA, we have means to prove that this incident has nothing to do with us," Pyongyang's official Korean Central News Agency (KCNA) quoted a spokesman as saying.
US Ambassador Samantha Power dismissed the demand for a joint probe, saying this "is exactly the kind of behavior we have come to expect from a regime that threatened to take 'merciless countermeasures' against the US over a Hollywood comedy, and has no qualms about holding tens of thousands of people in harrowing gulags," Power said on Monday, while attending a UN Security Council meeting on North Korea's human rights record.
South Korea nuclear power plant hacked
Meanwhile, South Korea on Monday said computer systems at its nuclear power plant operator had been hacked and that non-critical data had been taken, Reuters news agency reported.
Reuters said South Korean prosecutors had requested the US to help in their investigation of the attack, quoting an official on Tuesday, who said prosecutors were not ruling out that Pyongyang was behind the attack.
sb/jm (Reuters, AFP)