National Security Adviser Wi Sung-lac attends a press conference at the presidential office Cheong Wa Dae in Seoul, South Korea. Photo by YONHAP / EPA

July 22 (Asia Today) -- South Korea has not determined who was responsible for a cyberattack on a Foreign Ministry training system and is investigating several possibilities, the country's national security adviser said Wednesday.

Wi Sung-lac, director of the presidential National Security Office, also rejected allegations that the government attempted to conceal or minimize the breach.

"There was no intention to hide anything or deceive the public," Wi told reporters at the presidential office.

He said the government delayed publicly disclosing the incident because officials first needed to address information that posed urgent national security concerns.