The commander of U.S. Cyber Command and director of the National Security Agency visited Seoul to meet with South Korean Defense Minister Kim Kwan-jin to discuss cyber security issues, the defense ministry here said Tuesday.

U.S. Army Gen. Keith Alexander made a one-day visit to Seoul on Monday after his stop in Japan, as part of his trip to close allies before stepping down in March. The four-star general last year announced his plan to retire after the NSA was rocked by the worldwide spying scandal sparked by whistleblower Edward Snowden.

"As General Alexander is commander of the U.S. Cyber Command, the two discussed how to cooperate in a wide range of cyber security areas and evaluated threats posed by North Korea," defense ministry spokesman Kim Min-seok said in a briefing, without giving details of the closed-door meeting.

Washington has recently said through diplomatic channels that the NSA has not spied on South Korean President Park Geun-hye, a government source spoke on condition of anonymity, in an apparent effort to dispel lingering suspicions after a list of foreign leaders under U.S. surveillance surfaced, taking the world by surprise.

As part of sweeping reforms in the NSA, U.S. President Barack Obama last month announced plans to end spying on foreign leaders of close allies. (Yonhap News)