South Korea said North Korea fired artillery shells that landed near the sea border between the two countries late Tuesday, a day after Seoul began annual military drills in the region.
South Korea's Joint Chiefs of Staff said in a statement that North Korea fired about 100 shells off its west coast and 150 rounds off its east coast. Seoul said its military broadcast messages several times asking North Korea to stop the firing, but there were no reports of violence between the rivals.
South Korea said the shells did not land in its territorial waters, but rather in the maritime buffer zones the two Koreas established under a 2018 inter-Korean agreement aimed at reducing direct conflict.
It was the second time North Korea fired shells into the buffer zones since last Friday, when it shot hundreds of shells there.
In recent weeks, North Korea has conducted an array of missile and artillery launches in what some experts call an attempt to expand its weapons arsenal and boost its leverage in future negotiations with its rivals. Pyongyang sent one missile flying over Japan that landed in waters thousands of kilometers away.
North Korea said last week that its recent missile tests were simulations of nuclear strikes on South Korean and U.S. targets in response to their "dangerous" military exercises involving a U.S. aircraft carrier.
South Korea said North Korea must halt its tests that undermine peace and stability on the Korean Peninsula. Seoul said it is closely monitoring North Korean moves in coordination with the United States.
South Korea's military began its annual 12-day field exercises on Monday, an effort to sharpen its operational capabilities. It said an unspecified number of U.S. troops are taking part in this year's drills.
Some material in this report came from The Associated Press.