INCHEON (Yonhap) -- South Korea's Coast Guard said Wednesday it will request warrants to formally arrest the captains and senior crew members of two Chinese fishing boats that were seized while operating illegally in the neutral waters between two Koreas earlier this week.

The country's military police captured the boats in the neutral waters of the Han River estuary on Tuesday and turned them over to the Coast Guard.

It was the first time Chinese boats were captured in the area since the South Korean military kicked off its crackdown last Friday.

The Coast Guard said it is interrogating 14 crew members of the 35-ton boats and plans to arrest the two captains, aged 45 and 37, respectively, and four other senior crew members. The remaining eight members will be booked without physical detention.

The latest seizure is a continuation of Seoul's joint operation with the United Nations Command launched to deal once and for all with Chinese boats fishing without permission in the tense border area.

The military issued verbal warnings to disperse the boats but took action when they did not leave the area, the Joint Chiefs of Staff said Tuesday. It said the crew strongly resisted and even threw fishing equipment at the troops.

The crew said they departed from a port of Donggang near the Sino-North Korean border in early April and entered the estuary in early June, according to authorities.

Still, local authorities are carrying out their probe based on the possibility that the boats started their illegal fishing activities from April onwards.

The development comes after Seoul reported a growing number of Chinese fishing boats trespassing into the military buffer zone as blue crab season went into full swing. The intrusions have fueled security concerns over the closely monitored front-line region.

Besides crabs, the no man's land where the Han River meets the Yellow Sea is a rich fishing zone that had been left largely untouched since the 1950-53 Korean War.