A group of 21 North Koreans including children have been found adrift off the South's western coast, according to the South Korean coastguard. The group immediately expressed wish to defect after being found off Socheong island in the Yellow Sea early Tuesday, a coastguard spokesman announced on Saturday. They arrived at the western port of Incheon later that day on board a patrol boat, with their own vessel being towed in, the spokesman added. The 21 have since then been under interrogation by a joint team of investigators. It was not immediately clear why the coastguard did not announce the rescue for four days. Hundreds of North Koreans each year flee hunger and repression in their isolated communist homeland. They normally escape on foot to China, hide out and then travel to a third country to seek resettlement in South Korea. Beijing repatriates those whom it catches, calling them economic migrants. Seoul's policy is to accept all North Koreans who wish to stay in the South, while repatriating those who stray across the sea border by accident. Nine North Korean refugees including three children were picked up by Japan's coastguard in September after leaving the North's east coast. They arrived in South Korea last month. In another case, two North Koreans were also admitted to the South last month after they were found adrift in a small boat off its east coast.