SEOUL, South Korea (AP) — The rival Koreas exchanged warning shots along their disputed western sea boundary on Monday, their militaries 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 broadcast warning and fired warning shots to repel a North Korean merchant ship that it says violated the sea boundary early Monday.

North Korea’s military said it’s 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 on the pretext of cracking down on an unidentified ship.

South Korea’s Joint Chiefs of Staff said the North Korean artillery launches breached a 2018 inter-Korean accord on reducing military animosities and undermines stability on the Korean Peninsula. It said the North Korean shells didn’t land in South Korean waters.

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.

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

The missile launches were largely designed to protest U.S.-South Korean trainings near the Korean Peninsula that involved an U.S. aircraft carrier for the first time in five years. North Korea said its artillery firing drills were staged as countermeasures against similar South Korean artillery drills at border areas.

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.

South Korean military is under annual field exercises set to end this Friday. This year’s drills involve an unspecified number of U.S. troops.

Next week, South Korea and the United States are to hold joint air force drills involving some 240 warplanes, including F-35 fighters operated by both nations. The drills are aimed at inspecting the two countries’ joint operation capabilities and improve combat readiness, the South Korean military said Tuesday.

Some experts say North Korea’s recent missile tests suggest its leader Kim Jong Un has no intentions of resuming stalled nuclear diplomacy with Washington anytime soon as he would want to focus on further modernizing his nuclear arsenal to boost his leverage in future negotiations with the United States.

As reported by VINnews