Police and fire authorities will conduct a second joint inspection to find out the exact cause of a fire at a building belonging to the KT telephone company in Seoul on Saturday.

The National Forensic Service will also join the inspection set for 10 a.m. Monday in Ahyeon district in western Seoul.

Following the initial inspection on Sunday, police found that about 80 meters of the 150-meter cable tunnel in the basement was burnt, but could not determine where the fire started. 

Meanwhile, KT said that as of 6 p.m. Sunday, they have fixed 63 percent of the mobile network and 97 percent of the Internet lines, including those related to credit card transactions.