The National Intelligence Service says it is considering a variety of measures to tighten security against terrorism.
The director of the spy agency made the remarks at an annual parliamentary inspection of the agency on Thursday.
He said the security measures include designating no-fly zones over World Cup stadiums during the World Cup finals next year.
He told lawmakers that the spy agency has obtained the list of about two thousand suspected terrorists from 57 countries and plans to block their entry into the country.
The spy chief also said the government will tighten security around facilities used by U.S. forces stationed in South Korea.