NEW : Attack traced to IP address in China , officials say . Government computer networks did not seem to be affected , Yonhap cited the National Computing and Information Agency as saying . Comment: Banks , broadcasters targeted ; government networks unaffected , Yonhap reports . South Korean military steps up its cyberdefense efforts in response .
NEW : Attack traced to IP address in China , officials say . Comment: Banks , broadcasters targeted ; government networks unaffected , Yonhap reports . South Korean military steps up its cyberdefense efforts in response .