South Korea's top mobile carrier SK Telecom Co. said Monday it plans to purchase a local security firm to expand its business portfolio and seek synergy with its information and communication technology.

The firm said it will buy NSOK Co., South Korea's No. 4 security and guard company, by the end of this month. SK Telecom has not yet revealed details of the deal, including the price.

Industry watchers said SK aims to use its telecommunications technology in entering the security business and challenge its local rival KT Corp.

KT currently holds KT Telecop, the country's No. 3 security company, under its wing. Last year, SK made efforts to buy ADT Caps, the No. 2 local player, but the plan was scrapped after the two reportedly failed to agree on a price.

While KT Telecop's market share slightly hovers above that of NSOK, market watchers expect the smaller firm will quickly catch up to bigger rivals on the back of SK Telecom's strong dominance in the communications market.

Currently, SK Telecom controls roughly half of the country's mobile communication market, followed by KT and the smallest player, LG Uplus Corp. (Yonhap News)