North, South Korea trade fire over violation of maritime border

The rival Koreas exchanged warning shots along their disputed western sea boundary, their militaries have said, amid heightened tensions over North Korea’s recent barrage of weapons tests.

South Korea’s Joint Chiefs of Staff said in a statement that its navy fired warning shots to repel a North Korean merchant ship that it says violated the Northern Limit Line (NLL), the de facto sea boundary between the two Koreas on early Monday.

North Korea’s military said it has responded by firing 10 rounds of artillery shells as a warning to South Korea. It accused a South Korean navy ship of intruding into North Korean waters.

"The General Staff of the Korean People's Army ... ordered to fire 10 shots from multiple rocket launchers to sternly send back the enemy's vessel," the North Korean spokesman said in a statement carried by the KCNA.

There were no reports of clashes between the Koreas.

The poorly marked sea boundary off the Korean Peninsula’s west coast is a source of long-running animosities between the Koreas. 

It’s a scene of several bloody inter-Korean naval skirmishes and violence in recent years, including the two attacks in 2010 that killed 50 South Koreans.

READ MORE: 'Continuing provocations': North Korea fires artillery into buffer area

Rising tensions

In recent weeks, North Korea has carried out a string of weapons tests in response to what it calls provocative military drills between South Korea and the United States. 

Since September 25, North Korea has fired 15 missiles and hundreds of artillery shells toward the sea.

Seoul and Washington routinely conduct military drills to maintain their readiness against potential North Korean aggressions. 

The allies say their drills are defensive in nature, but North Korea views them as an invasion rehearsal.

The South Korean military is under annual field exercises set to end this Friday. 

This year’s drills involve an unspecified number of US troops.

Some experts say North Korea's recent weapons tests are also designed to bolster its arsenals to boost its leverage in future negotiations with its rivals.

READ MORE: South Korea begins military drills amid North's nuclear tests