Seoul, South Korea (CNN) -- South Korean police said Wednesday they are investigating a widespread computer outage that has struck systems at leading television broadcasters and banks, prompting the military to step up its cyberalert level amid concerns about North Korea.

The South Korean communications regulator reportedly linked the computer failures to hacking that used malicious code, or malware.

Networks at the different companies began to encounter difficulties starting around 2 p.m. local time (1 a.m. ET).