North Korea
North KoreaReuters

A senior official of the North Korean military spy agency defected to South Korea last year, Seoul said Monday. The defector, an Army colonel specialised in espionage, is the highest-level official to have defected from the Kim Jong Un-led country and has been granted political asylum in South Korea.

In another high-level defection, a North Korean diplomat who was positioned in an African country escaped to South Korea with his family in May last year, a source told Yonhap News Agency.

"(The North Korean military official's defection) is a fact, but we cannot make public detailed information (about him)," Moon Sang-gyun, a ministry spokesman, was quoted as saying by Yonhap.

The colonel worked for North Korea's reconnaissance bureau that focuses on spying on South Korea, Reuters reported.

"He [the colonel] is believed to have stated details about the bureau's operations against South Korea to authorities here," a source said.

At least 70 officials have been reportedly executed ever since Jong Un became the supreme leader of the country in 2011, Yonhap quoted South Korea's spy agency, National Intelligence Service (NIS), as saying.

In another incident, almost a dozen North Korean civilians defected to South Korea last week after working in China. They reportedly travelled to South Korea through Laos and Thailand.

The Unification ministry of South Korea has been tight-lipped about the details of both cases, but it confirmed the defections. The ministry also said that the defection of the high-ranked colonel exposes the cracks in the leadership of the North.

Tension between South and North Korea has been high ever since Pyongyang test-fired nuclear and ballistic missiles. Pyongyang accused the U.S. and South Korea of preparing to attack the North after they conducted annual naval exercises. North Korea, which violated sanctions by testing missiles, has been slapped with more sanctions even as it is struggling to fund its nuclear programme.