North Korea on Thursday demanded the return of nine people who defected to the South, warning that relations between the two countries would worsen otherwise, dpa reported.
The nine should be returned with the boats they escaped in, according to a statement from the North Korean Red Cross to its counterparts in the south.
The nine North Koreans reached the South after sailing across the disputed maritime border, officials said Wednesday. They were picked up at sea by the South Korean military on Saturday, the South's Yonhap News agency quoted officials as saying.
The group consisted of three men, two women and four children, the official said, speaking on condition of anonymity.
In February, a group of 31 North Korean fisherman was found in South Korean waters. After tense negotiations with Pyongyang, 27 were returned to the North, while the remaining four stayed in the South as they had requested, Seoul officials reported at the time.
Impoverished North Korea has announced plans to become a prosperous and powerful country by next year, the anniversary of the birth of the country's revered founder Kim Il-sung.
But recent appeals for aid and reports of chronic food shortages and forced labour camps suggest that conditions are increasingly difficult for the population.