Ri Il-kyu had been in charge of political affairs at Pyongyang's embassy in Cuba since 2019 and was tasked with "obstructing the establishment of diplomatic relations between South Korea and Cuba," according to the daily.
Ri defected to South Korea with his wife and children in early November, making him the highest-ranking North Korean diplomat known to defect to the South since Thae Yong-ho, Pyongyang's deputy ambassador in London, fled in 2016, he added.
The South Korean Ministries of Unification and Foreign Affairs said they could not confirm the defection.
The Ministry of Unification has already reported an increasing number of defections by members of the North Korean ruling class, or around ten of the 196 defections recorded last year, the highest number in recent years.
About three months after the announcement of Ri's defection, South Korea and Cuba, a communist country and one of Pyongyang's oldest allies, announced the establishment of diplomatic relations.
In an interview with Chosun Daily, Ri said he decided to defect after Pyongyang rejected his request for medical treatment in Mexico for an injury, although he was unable to receive the necessary treatment in Cuba due to a lack of specialized equipment.
The young man also alleged that he was the subject of unfair evaluation reports, after rejecting a request for a bribe from an official at the North Korean Ministry of Foreign Affairs.
"Every North Korean thinks at least once about living in South Korea," he told Chosun Daily.
"Disillusionment with the North Korean regime and a bleak future led me to consider the possibility of defecting," he said.
The former diplomat also indicated that former North Korean Foreign Minister Ri Yong-ho and his family had been sent to a political prison camp in December 2019 on "suspicion of corruption", as part of a case of bribery involving the North Korean embassy in Beijing.
