Two Chinese fishing trawlers near a North Korea island near the Northern Limit Line between the two Koreas. Pyongyang disputes the maritime border. File Photo by Yonhap

SEOUL, June 30 (UPI) -- South Korea fired warning shots at a ship traveling from North Korea, when it crossed a disputed maritime border on Tuesday.

The unidentified boat from the North retreated back to Pyongyang's side of the Northern Limit Line soon after the shots were fired at 10:22 a.m., according to South Korean news agency Yonhap.


This is not the first case of a boat from North Korea trespassing the NLL, a boundary recognized by Seoul and Washington, but disputed by Pyongyang.

South Korean newspaper Kyunghyang Sinmun reported in 2015 that North Korea boats crossed the boundary eight times.

On May 10, North Korea had dispatched boats to standby along the NLL, according to South Korea press.

The boat on Tuesday had crossed into the South and had traveled 0.8 nautical miles when the South Korea navy intercepted the vessel and issued a message of warning.

Warning shots followed and the boat retreated without retaliation, according to South Korea's Joint Chiefs of Staff.

The South Korea vessel that intercepted the trespassing one was not a combat-ready ship.

South Korea determined the boat had traveled from the North when it could not be identified after it crossed the NLL.

South Korea's military said it was strengthening its monitoring capabilities in the Yellow Sea, and that it was staying combat ready.

Seoul's Defense Minister Han Min-koo recently told members of parliament the North is making efforts to neutralize the NLL through the placement of 10 boats along the maritime border that violates North Korea sovereignty, according to Pyongyang.

In May, North Korea claimed South Korean naval boats in the Yellow Sea had repeatedly entered territorial waters belonging to North Korea.