South Korea's top mobile service provider SK Telecom Co. apologized Friday for an overnight service failure observed throughout the country, which left its 20 million users unable to use normal services.

"We deeply apologize for any inconvenience caused by the service failure," the company said in its press release. "We will provide users with more details on compensation in the future."

The announcement came as SK Telecom's mobile network partially suffered a failure on Thursday night through early Friday morning, with its subscribers having problems in making calls and downloading data such as emails and maps.

Other transaction systems using SK Telecom's mobile network were also reportedly suspended during the cited period.

SK explained the problem was sparked by an error in its Home Location Register, which is used in detecting the position of callers. Although the error was immediately taken care of, the excessive number of calls standing by caused an overload in the network traffic, it added.

"Our compensation will not be limited to our policies," added Ha Sung-min, who heads SK Telecom. "We will again find more details about what caused the accident and return to the basics."

The company's policy states that it must compensate users when they are unable to use services for more than three hours, with an amount that is more than six times the costs to subscribers during a failure.

SK Telecom accounts for around half of the South Korean telecom market, trailed by KT Corp. with 30 percent and LG Uplus Corp. with 20 percent.

It marked the second time for SK Telecom's service to be temporarily suspended this year, after its data network suffered a failure for 20 minutes on March 13.

South Korea's Ministry of Science, ICT and Future Planning said it plans to issue a correction order against SK Telecom if its follow-up actions are unsatisfactory, adding it has also ordered the firm to operate a special team to oversee complaints from users concerning the loss of service. (Yonhap)