Seoul, Oct 23 (IANS): South Korea is investigating the mysterious disappearance of a North Korean defector couple who might have returned to their country, a top Unification Ministry official said on Monday.

It is not yet known if the couple, in their early 30s, returned to their country of their own will or if they were apprehended by North Korean authorities from border areas of China, the official told Efe news.

"We know that the couple was in China in mid-October but we lost contact after that," he added.

In a press conference on Monday, the ministry said that out of 31,093 North Koreans who have fled to South Korea so far, 26 have returned to their country.

According to government and nonprofit reports, most North Korean defectors work in low-paid jobs and often face prejudice in South Korea, leading to psychological distress.

In July, a well known female defector - a regular on South Korean TV panels - returned to North Korea and appeared in a propaganda video, criticising living conditions in Seoul, although owing to the opacity of the regime, it is impossible to determine if the interview was voluntary or forced by the government.