Facilities with a D classification are mostly small and have so far been "self-examined" by mobile carriers and Internet operators that operate such places, officials said.

The ministry said it also plans to mandate installing CCTVs and sprinklers in cable tunnels shorter than 500 meters in length.

In addition, the ministry will set up a task force team to come up with detailed plans to prevent major telecommunication disruptions by the end of this year.

On Saturday, a fire broke out in the basement of the telecommunications company building and burned about 150 meters of fiber optic cables installed underground, paralyzing the fixed-line, mobile and Internet networks for individuals and businesses using KT in Seoul's western districts of Mapo, Seodaemun and Eunpyeong, as well as some parts of Gyeonggi Province surrounding Seoul. (Yonhap)