South Korea's Coast Guard and Navy continued their search on Sunday for the body and belongings of a fisheries official shot to death by North Korea last week.

The Coast Guard said it is conducting an intensive search in the waters near Yeonpyeong Island in the Yellow Sea near the inter-Korean maritime border.

Authorities mobilized 39 vessels, including naval ships and six aircraft for their operation, which is five times larger than the previous day.

Regarding North Korea's warning against violating the North's territorial waters, a Coast Guard official said that the search is strictly taking place south of the Northern Line Limit (NLL), a de facto maritime border.

Meanwhile, authorities are looking into the ill-fated official's activities before the killing, including a possibility that he attempted to defect to the North.

The Coast Guard is carrying out a digital forensic probe on a computer on the fishery patrol ship which the official had boarded, to find out if there were any search records related to North Korea.