A high-ranking North Korean military officer who was in charge of spying operations has defected to South Korea, according to Seoul's defence ministry.
Few details have been released about the man, but he is a colonel and is considered an elite, South Korea's Yonhap news agency reports.
He is believed to have shared details with South Korean intelligence about the secretive northern regime's operations.
It is being seen as the latest sign of cracks in North Korea's leadership.
In 2015 South Korea's spy agency said North Korean leader Kim Jong-un has had more than 70 senior officials executed since he took power, in an effort to tighten his grip on the communist regime.
Last week, a group of 13 North Koreans who used to work at an overseas restaurant defected en masse to South Korea, the first mass defection since 2011, Yonhap reported.
The defectors reportedly escaped to South Korea via Thailand from the Chinese port city of Ningbo, where they were working.
The developments follow tougher sanctions on North Korea from the UN and major countries for its January nuclear test and long-range rocket launch in February.
There are more than 28,000 North Korean defectors in South Korea, with some 1,280 North Koreans entering the South last year, according to Seoul's unification ministry.