"Thae Yong-ho, who was Pyongyang's No. 2 diplomat to Britain, is open to the public. But there could be figures who also defected but have not been disclosed," the lawmaker said. Thae defected to South Korea last year, and has been making various public appearances to deliver testimony on the North Korean regime.

North Korean leader Kim Jong-un's half brother, Kim Jong-nam, was killed by poison in Malaysia earlier this week in an apparent assassination. Following the incident, South Korean police increased the number of officers protecting high-ranking North Korean defectors in the country including Thae.

The lawmaker said Kim Jong-nam's children, including Han-sol, could also be targets. Kim Jong-nam's first wife is currently staying in Beijing with a son, while his second wife is living in Macao with a son and a daughter. All of them are currently under the protection of Chinese authorities, intelligence sources said.

"(The incident) clearly reflected Kim Jong-un's violent character," the lawmaker said, claiming such an attitude could also be reflected in North Korea's policies. (Yonhap)