Seoul: North Korea returned six detained South Koreans across the two rivals` heavily-militarised land border on Friday, in a move that may help relax tensions.
The handover took place at 4:50pm (0750 GMT) at the Panmunjom truce village where the armistice was signed ending hostilities in the 1950-53 Korean War, the South`s Unification Ministry said.
All six were men between the ages of 27 and 67, but their precise identity and the circumstances that led to their detention in the North were unclear.
The Unification Ministry, which was only informed Thursday of the North`s intention to return the men, said details would be released after they had been questioned.
North Korea said in February 2010 that it was holding four South Koreans who had "illegally entered" the country -- and it is presumed that they are among the six returnees.
Seoul had repeatedly requested the four to be identified and released, but there was no response from Pyongyang.
The surprise return of the six South Koreans would appear to be a conciliatory gesture at a time when North-South ties have been blowing hot and cold.
Tensions soared for months after the North`s third nuclear test in February, but then appeared to enter a rapprochement stage that saw the two rivals agree to re-open their joint industrial park in Kaesong.
But the mood quickly soured again when Pyongyang cancelled a scheduled reunion last month for family members separated by the Korean War.
Some heated rhetoric followed, but then earlier this week Pyongyang agreed to a request by South Korean lawmakers to visit Kaesong -- which lies just inside its side of the border -- for an inspection tour.
Border crossings between North and South are extremely rare and it is most likely that the six people returned on Friday had entered North Korea from China.
There has been speculation that they might have been connected to Christian missionary groups who are active in helping North Koreans escape the country.
The six could face criminal charges, as South Korea`s National Security Law prohibits its citizens from entering the North without official permission.