Joo Won-moon, who has permanent US residency and studied at New York University, was handed over at the border truce village of Panmunjom on the heavily militarized frontier separating the two Koreas late on Monday afternoon, the South Korean Unification Ministry said.

Officials said Joo would be questioned by South Korean authorities about his unauthorized stay in the North.

Joo was arrested in April after crossing into North Korea from the Chinese border city of Dandong. In May, he told American broadcaster CNN in an interview that he thought that his act "could have a good effect on the relations between the North and [South Korea]."

A number of foreigners, many of them Americans and evangelical Christians, have entered the communist nation over the years. They are usually released by the North after a short prison term.

Joo's release came just days before the North celebrates the 70th anniversary of the ruling Workers' Party on Saturday, and the move is likely to be seen as a goodwill gesture.

More releases urged

South Korea welcomed the decision to free Joo, and called on North Korea to release three other South Korean people still in detention.

Two were sentenced to life imprisonment with hard labor in June, charged with spying, while a Korean-Canadian missionary was given a similar sentence in May 2014 on the same charges.

The two Koreas, which are still technically at war after a 1950-1953 conflict ended only with an armistice, in August agreed to improve ties after a number of tense incidents at the border threatened to become an armed conflict.

Later this month, families separated by the Korean War will be meeting for a reunion, only the 20th time such an event has taken place in more than 60 years.

tj/msh (AFP, Reuters)