Seoul, South Korea(CNN) A North Korean senior intelligence officer has become the highest-ranking military official to defect to South Korea, a government source confirmed to CNN.
The defector was a senior colonel with the North Korean Reconnaissance General Bureau, which is in charge of espionage operations against South Korea, according to South Korean Defense Ministry spokesman Moon Sang-gyun and Unification Ministry spokesman Jeong Joon-hee.
North Korea's Reconnaissance General Bureau is a powerful body, responsible for clandestine operations, including espionage against foreign countries and cyberwarfare operations.
Speaking in separate news conferences Monday, the ministry spokesmen confirmed that reports from South Korea's semiofficial Yonhap News Agency on the defection were accurate but said they could give no further details. The colonel had defected last year, according to Yonhap, but CNN cannot independently confirm this.
The announcement of the high-level defection followed news last week that 13 North Korean nationals who had been working at a Pyongyang-owned restaurant had defected to South Korea, officials in Seoul announced. The restaurant workers, 12 women and a man, said they had defected after "feeling pressure from North Korean authorities" to send foreign currency back to their homeland, South Korean officials said. A Chinese foreign ministry spokesman confirmed that 13 North Koreans who worked in a Pyongyang-owned restaurant in China left the country legally on April 6.
On Tuesday, North Korea threatened defectors in a commentary published in its state-run propaganda site Uriminzokkiri, calling them "gangsters little short of thrusting daggers into the lifeline of all families in the DPRK."
Many defectors have expressed concern for their family members who remain in North Korea as the regime is said to practice guilt by association -- in which people closest to the individual are punished.
The North Korean commentary threatened those who defected to South Korea of "pre-emptive, consecutive attack on them in a more deadly and severe punishment without any warning and prior notice."
All North Korean defectors are interviewed by South Korean intelligence services for information about life across the border.
It is expected the latest, high-profile defector could prove a rich trove of knowledge about the workings of North Korean leader Kim Jong Un's secretive regime.
Tens of thousands of North Koreans have fled poverty and repression in the isolated North in recent decades, but defections of senior officials are less common. In the first quarter of 2016, North Korean defections to South Korea rose by 17.5 percent compared with the previous year. Between January to March, 342 North Koreans fled to the South, Yonhap reported.
Last year, a high-level defector told CNN that Kim was taking an increasingly brutal approach to the elite, executing them when they fell out of favor.
The hard line on aides and officials was eroding Kim's fragile support base, the defector said, in comments CNN was unable to confirm independently because of the challenges of verifying information inside North Korea, one of the world's most closed societies.
North Korean defector: Kim will lose power within three years
Tensions have ratcheted up on the divided Korean Peninsula this year as Pyongyang has made a series of assertions about developments in its military capability.
Last week, Pyongyang's state-run news agency KCNA said North Korea had successfully tested a new engine for an intercontinental ballistic missile.
Pyongyang carried out its fourth nuclear test in January, and last week said it had succeeded in miniaturizing nuclear warheads to fit on medium-range ballistic missiles -- which officials in Seoul said they believed was true.
How North Korea's nuclear program went from threats to reality