SEOUL, May 11 (Xinhua) -- South Korea and the United States are considering to conduct more drills against cyber attacks in their annual defense exercise, South Korea's Yonhap News Agency reported on Sunday.

    South Korea and the United States are discussing the possibility of reinforcing drills against cyber attacks starting from this year' s Ulchi Focus Guardian exercise, Yonhap quoted an unnamed South Korean military official as saying.

    The drill, if conducted, will involve a number of intelligence and Internet security officials from various organizations, including the country's Defense Security Command, Yonhap said.

    According to the South Korean Defense Ministry, a total of 278 computers at 10 government offices and institutes, such as the Korea Institute of Defense Analysis and the Korea Atomic Energy Research Institute, were infected with hacking viruses in 2004.

    The military's systems have so far been free from hacking attempts as they run on an intranet, completely cut off from the Internet, it said.