A group of high-ranking North Korean officials have reportedly fled to the South amid growing anxiety over Kim Jong-un's brutal reign of terror.
The latest of a series of such defections includes a high-ranking official in charge of Pyongyang's munitions industry.
Sources told reporters that the government was able to gain considerable information on the repressive state's nuclear power and missile industry from this defector.
Another official from the North's ruling Workers' Party, who was in charge of supervising a military industrial area, is also reported as having defected to the South.
On Friday, it was reported that Park Seung-won, a three-star general of the North Korean People's Armed Forces, escaped and arrived in the South via Russia in April.
Park attended the inter-Korean defense chiefs' talks in 2000 on Jeju Island as the official ranked second in command.
Three high-ranking officials of the ruling Workers' Party, in charge of managing Kim's secret funds, also allegedly came to the South.
The Ministry of Unification refused to confirm the defections.
"It is hard to confirm this. Moreover, it is improper for me to talk about it at this place (a regular briefing)," the ministry spokesman Jeong Joon-hee said, Monday. "I will tell you later when there is something additional."
Experts on North Korea say that Kim's reign of terror might have prompted a series of defections by high-ranking officials.
"They probably felt insecure because Kim has executed a number of high-level officials who offended his eyes, even slightly," said Park Young-ho, senior researcher at the Korea Institute for National Unification.
"The defectors might have been related to those purged, and believed that they would be the next targeted for execution. The defections were probably motivated by self-preservation."
The National Intelligence Service (NIS) confirmed in May that Hyon Yong-chol, the chief of the People's Armed Forces, was killed by anti-aircraft gunfire on April 30 for dozing off during a military meeting presided over by Kim and failing to obey his instructions.
Others executed included Ri Yong-ho, former vice marshal, and Jang Song-thaek, the No. 2 man in Kim's regime and the leader's uncle. They were killed in 2012 and 2013, respectively.
According to the NIS, about 70 officials have been purged during Kim's dictatorship so far.
Follow Jun Ji-hye on Twitter @TheKopJihye