The vessel with three sailors aboard was seized south of the disputed
Yellow Sea border late Thursday. It had refused to retreat despite warning
shots from a South Korean naval ship.
An overnight investigation found the vessel could not sail north because of
a sudden engine failure, the South's Joint Chiefs of Staff said.
The vessel was handed over to a North Korean naval ship early Friday after
its crew told investigators that they had no intention to defect, it said.
The South's navy has told its North Korean counterpart that the seizure was
aimed at ensuring the safety of the crew.