Two Koreas exchange warning shots along western border

South Korea's military on Monday said it has fired warning shots at a North Korean ship that crossed the Northern Limit Line (NLL) in the Yellow Sea, the de facto maritime border, while the North also opened "warning fire" against the South in response.

A North Korean merchant vessel violated the NLL in waters near the front-line island of Baengnyeong at 3.42 a.m. and it retreated northwards after the South's Navy issued warning messages and fired some 20 rounds of warning shots, according to the South's Joint Chiefs of Staff (JCS).

Shortly after the announcement, the North Korean military claimed a South Korean warship violated the western sea boundary and it fired 10 artillery shells into the western sea from multiple rocket launchers in its "threatening and warning fires", reports Yonhap News Agency.

The South Korean escort ship "invaded" the Military Demarcation Line controlled by the North's military by 2.5-5 km at 3.50 a.m. on the excuse of cracking down on an unidentified vessel, an unnamed spokesman for the General Staff of the Korean People's Army (KPA) said in a statement.

The South's JCS said it detected the North's launch of 10 artillery shells, which started at around 5.14 a.m., in violation of a 2018 inter-Korean military agreement aimed at reducing border tensions.

It also added multiple South Korean naval vessels, including a frigate, were deployed near the area, but they did not cross the NLL.

The North's ships have frequently intruded past the NLL, as it has long demanded that the line be moved farther south.

The North does not recognize the border, arguing it was unilaterally drawn by the US-led UN Command after the 1950-53 Korean War.

The two Koreas fought bloody battles there in 1999, 2002 and 2009.

The exchange of warning fire between the two Koreas came amid heightened tensions on the peninsula amid North Korea's continued provocations, including a barrage of ballistic missile tests and firing of artillery shots.

Pyongyang has carried out a string of weapons tests in recent weeks in response to joint military exercises between Seoul and Washington, which the North views as rehearsals for an invasion against it.