North Korea returned six South Korean men it had detained on charges of illegal entry to their home country.
The men, between the ages of 27 and 67, were handed over to South Korean authorities on Friday at the border village of Panmunjom.
Their names have not been released.
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Little is known about their detention in the North and the Unification Ministry said it would question the men about the details surrounding their arrival in the country. Traveling to the North without government permission is a violation of the South's National Security.
The North's decision came just as Pyongyang approved a tour of the jointly run Kaesong industrial complex for 24 South Korean lawmakers next week.
However, the North also abruptly canceled family reunions for those separated during the '50s Korean War last month.
For the past three years, Pyongyang claimed it detained several South Koreans for entering the North illegally, but would not provide their identities or other details.
While approximately 25,000 North Koreans have defected to the South over the past 20 years, some South Koreans fleeing legal, fiscal or marital problems have also crossed into the North.