Access to major North Korean websites remained unstable Saturday for the fifth straight day following U.S. hints at cyber retaliation last week.

The homepages of the North's main propaganda organ, Uriminzokkiri, and three other sites whose servers are based in China were inaccessible Saturday morning, since going down on Friday evening.

The website of Chosun Shinbo, a newspaper published by the General Association of North Korean Residents in Japan, could be accessed only intermittently.

Meanwhile, the homepage of the North's official Korean Central News Agency and the communist party's official newspaper, Rodong Sinmun, were stable.

North Korea experienced sweeping Internet outages for hours before coming back online on Tuesday following a cyber security row with the U.S.

U.S. President Barack Obama had earlier pledged a "proportional" response to the recent hacking of Sony Pictures Entertainment that was blamed on Pyongyang. (Yonhap)