The Web sites of South Korea's presidential office and another government agency were shut down reportedly due to a breach by Anonymous hacktivist group on Tuesday.

According to Yonhap News on Tuesday, the cyberattacks had occurred around 9:30 AM South Korea time at the home pages of Cheong Wa Dae, and the Office of Government Policy Coordination. Both Web sites have been shut down for repair.

Immediately after the hacking attack, the Cheong Wa Dae Web site showed messages in red, including one that read "Great Leader Kim Jong-un", the North's top leader, the report noted.

For 10 minutes from 10 AM South Korea time, it was posted along with the message "We Are Anonymous. We Are Legion. We Do Not Forgive. We Do Not Forget. Expect Us," along with a photo of President Park Geun-hye.

Both Web sites now show messages stating it has been temporarily suspended. When ZDNet Asia accessed the Cheong Wa Dae Web site at 10:45 AM Singapore time, the message displayed stated, "This Web site is temporarily out of service due to a system check."

Anonymous had said in April it will launch cyberattacks on dozens of North Korean Web sites on Tuesday, the 60th anniversary of the outbreak of the 1950-53 Korean war, according to a separate report on Chosun Ilbo.

While it is not clear if the North is involved in this attack, security experts from the South in March this year believe North Korea has been training computer-savvy "cyberwarriors" , which may prove cheaper and faster than building nuclear devices or other weapons of mass destruction.