South Korean police Wednesday began an investigation into a series of cyber attacks on major Web sites including those for the presidential office of Cheong Wa Dae, the Defense Ministry and other government agencies.
Yonhap News Agency said the Cyber Terror Response Center, a division of the National Police Agency, has established a team to look into the case.
About 25 Web sites were attacked Tuesday evening, with service suspended for nearly four hours, according to reports.
The so-called denial-of-service attacks targeted government ministries, agencies and major Internet portal sites, Yonhap said, quoting officials at the state-run Korea Information Security Agency.
Denial-of-service attacks involve sending large amounts of data, prompting Web servers to be downed.
The Defense Security Command last month reported that the nation's military computer networks have been grappling with mounting cyber attack, with 95,000 cases reported daily on average.
Some of the sites still remain unstable.