Choe In-guk speaks at an airport in Pyongyang, Saturday. Courtesy of Uriminzokkiri

A South Korean son of Ryu Mi-yong, the late chairwoman of a North Korean minor political party, has arrived in Pyongyang to live in the communist country for good, a North Korean propaganda media outlet said Sunday.

Ryu and her husband, Choe Tok-sin, who served as foreign minister in South Korea during the 1960s, emigrated to the United States in 1976 and defected to the North in 1986, leaving behind two sons and three daughters.

In the North, Ryu served as chairwoman of the central committee of the Chondoist Chongu Party. She died of lung cancer at age 95 in November 2016.

On Saturday, Uriminzokkiri, one of the North's propaganda websites, reported that Ryu's second son, Choe In-guk, arrived in Pyongyang on Saturday for "permanent residence."

If confirmed, it would be a rare case of a South Korean national entering North Korea and publicly announcing a decision for permanent residence there.

Upon arriving at a Pyongyang airport, Choe said he will devote his life to helping achieve the feat of national unification in accordance with the desire of his late parents.

"To live in and follow a country for which I feel thankful is a path to protect the will left by my parents. So I've decided to permanently live in North Korea, albeit belatedly," the media outlet quoted Choe as saying.

The government is trying to find out the exact motive for the 73-year-old Choe's trip. He reportedly did not seek government approval for his trip to North Korea.

The outlet did not mention how Choe reached the North, but he appears to have arrived in North Korea by air via a third country.

Footage released by the propaganda website showed Choe receiving welcoming flowers from North Korean officials and reading out his statement at the airport.

His parents were ranking officials in North Korea. Choe's father served as a deputy head of an agency in charge of inter-Korean affairs and the chief of the Chondoist Chongu Party.

After his death in 1989, Ryu led the minor party and became a member of the Presidium of the Supreme People's Assembly, the North's rubber-stamp parliament.

The junior Choe was allowed by the South Korean government to enter North Korea in 2016 to attend his mother's funeral. He was also permitted to take part in his mother's memorial services in 2017 and 2018. (Yonhap)