North Korea has fallen victim to a massive cyber attack since Wednesday morning, a senior South Korean government official said. He added Seoul is trying to find out who is behind it.

"Internet resources of the country have come under a powerful hacker attack from abroad," Russia's ITAR-TASS news agency, which has a branch in Pyongyang, reported on Wednesday night. The country's websites apparently all went offline until late Thursday afternoon.

They included propaganda outlets like the Rodong Sinmun, the KCNA news agency and Naenara, which are blocked in South Korea.

An expert at a government-funded think tank in Seoul said it is unlikely that an attack on this scale was launched by an individual hacker since all websites with North Korea-based servers were affected and the attack lasted for two days.

The official insisted the South Korean government has nothing to do with it.

"It's inconceivable that the Internet network of the North has been under hacker attack for such a long period of time," said Ryu Dong-ryeol at the Police Science Institute. "It's likely that the regime has staged the incident itself as a way out of its current international impasse."